schedule for research scholar day 2014schedule for research scholar day 2014 venue: 5104...

SCHEDULE FOR RESEARCH SCHOLAR DAY 2014

VENUE: 5104

REGISTRATION : 8.30 AM – 8.55 AM WELCOME : 9.00 AM – 9.15 AM

Session I (9.15 AM – 10.45 AM) Speaker Title Time

Tridev Mishra Thermal Properties of a Particle Confined to a Parabolic Quantum Well in Two-Dimensional Space with Conical Disclination

9.15-9.30

C. Karthik Surface Studies on a Novel Discotic Liquid Crystalline Molecule 9.30-9.45 Sunita Joshi Fluorescence Quenching of Quinine Sulfate Dication: an indicator for sensing

Chloride ion in Ionic and Neutral Micellar Environments 9.45-10.00

Rituparna Bhattacharjee Variants of Hardness Potential: Development and Applications 10.00-10.15 Pankaj Nehra Synthesis, Characterization and Catalytic Applications of Palladium

Complex for C-C Coupling Reactions 10.15-10.30

Ravi Trivedi Density functional study of Hydrogen storage in small MgnCo clusters: A future energy solutions

10.30-10.45

TEA BREAK: 10.45 AM – 11.15 AM

Session II (11.15 AM – 12.45 PM)

Speaker Title Time Munesh Rathore Effect of Conditional Glass Former Variation on Electrical Transport in Li2O-

P2O5 Glassy and Glass-Ceramic Ionic System 11.15-11.30

Devnarayan VP Surface Plasmon Resonance Studies of Stearic Acid and Octadecanethiol Systems

11.30-11.45

Amar Singh DNA Unzipping due to Random Force 11.45-12.00 Keerti Choudhary Morphological and Electrical Characterization of Thin Film of TiO2

Nanoparticles 12.00-12.15

Monika Poonia Interaction of DNA and Langmuir Blodgett film of dioctadecyl ammonium bromide using QCM

12.15-12.30

Kapil Dhaka Shell Magnetism of Chromium Doped Germanium Superatom 12.30-12.45

LUNCH BREAK: 12.45 PM – 1.45 PM (INSTITUTE CAFETERIA )

Session III (2.00 – 2.45 PM) Speaker Title Time

Jitendra Kumar Effect of the Functionalized Carbon Nanotubes on the Physical Properties of Nematic Liquid Crystal

2.00-2.15

Amrit Sarmah A Density Functional Reactivity Theory Based Approach to Understand the Interaction between Aun (n = 3-6) Metal Clusters and Nucleobases

2.15-2.30

Pragati Fageria Synthesis of ZnO/Au and ZnO/Ag nanoparticles and their photocatalytic application using UV and visible light

2.30-2.45

POSTER SESSION & TEA: 2.45 PM – 4.15 PM

Session IV (3.30 – 4.15 PM)

Speaker Title Time Surendra Pratap Determination of Channel Electron Density of a Nano-MOSFET using

Quantum and Semi-classical Methods 3.30-3.45

Archana Choudhary Experimental and Theoretical studies of 'Ship-in-a-Bottle' Ni(II) Schiff base Complexes in Zeolite Y

3.45-4.00

Nisar Ahmad Mir Organocatalytic approach towards the synthesis five-membered nitrogen heterocycles

4.00-4.15

CONCLUDING REMARKS & VOTE OF THANKS: 4.15 PM – 4.30 PM

FOREWORDS

Research Scholar Day organized by the Department of Physics, BITS Pilani, Pilani campus is an

in-house symposium to facilitate sharing of research activities and exploring newer areas of

frontier research. The aim is to bring together the research scholars working in diverse areas of

science towards mutual appreciation and sharing of research aspirations.

We wish you all the best for your bright future.

Department of Physics

BITS, Pilani, Pilani Campus

Research Scholar Day 2014 Page 2

Table of Contents

ORAL PRESENTATIONS S.N. Title of the Presentation Presenter Page 1. Fluorescence Quenching of Quinine Sulfate Dication: an indicator for

sensing Chloride ion in Ionic and Neutral Micellar Environments Sunita Joshi 5

2. Variants of Hardness Potential: Development and Applications Rituparna Bhattacharjee

6

3. A Density Functional Reactivity Theory Based Approach to Understand the Interaction between Aun (n = 3-6) Metal Clusters and Nucleobases

Amrit Sarmah 7

4. Surface Plasmon Resonance Studies of Stearic Acid and Octadecanethiol Systems

Devanarayanan VP

8

5. Thermal Properties of a Particle Confined to a Parabolic Quantum Well in Two-Dimensional Space with Conical Disclination

Tridev Mishra 9

6. Shell Magnetism of Chromium Doped Germanium Superatom Kapil Dhaka 10 7. Effect of the Functionalized Carbon Nanotubes on the physical

properties of nematic liquid crystal Jitendra Kumar 11

8. Interaction of DNA and Langmuir Blodgett film of dioctadecyl ammonium bromide using QCM

Monika Poonia 12

9. Morphological and Electrical Characterization of Thin Film of TiO2 Nanoparticles

Keerti Choudhary

13

10. Effect of Conditional Glass Former Variation on Electrical Transport in Li 2O-P2O5 Glassy and Glass-Ceramic Ionic System

Munesh Rathore

14

11. Surface Studies on a Novel Discotic Liquid Crystalline Molecule C. Karthik 15 12. Synthesis of ZnO/Au and ZnO/Ag nanoparticles and their photocatalytic

application using UV and visible light Pragati Fageria

16

13. Experimental and Theoretical studies of 'Ship-in-a-Bottle' Ni(II) Schiff base Complexes in Zeolite Y

Archana Choudhary

17

14. Determination of Channel Electron Density of a Nano-MOSFET using Quantum and Semi-classical Methods

Surender Pratap

18

15. Synthesis, Characterization and Catalytic Applications of Palladium Complex for C-C Coupling Reactions

Pankaj Nehra 19

16. DNA Unzipping due to Random Force Amar Singh 20 17. Density functional study of Hydrogen storage in small MgnCo clusters:

A future energy solutions Ravi Trivedi 21

18. Organocatalytic approach towards the synthesis five-membered nitrogen heterocycles

Nisar Ahmad Mir

22


POSTER PRESENTATIONS S.N. Title of the Presentation** Presenter Page 1. Photophysics of Quinine Sulphate Dication in Micellar Environments Sunita Joshi 24 2. Effect of Nanosize Micelles of Ionic and Neutral Surfactants on the

Photophysics of Protonated 6-Methoxyquinoline: Time-resolved Fluorescence Study

Tej Verma 25

3. Surface Plasmon Resonance studies of Langmuir-Blodgett Films of Stearic Acid

Devanarayanan VP

26

4. Magnetic behavior in Cr2@Gen (1≤n≤12) Clusters: A Density Functional Investigation

Kapil Dhaka 27

5. Temperature Dependent Electro-optic and Dielectric Properties of CdSe

QD’s Doped Nematic Liquid Crystal

Jitendra Kumar 28

6. Study on Detection of Contamination in Water using Quartz Crystal Microbalance

Monika Poonia 29

7. Langmuir- Blodgett films of Stearic acid - Aligning agent for Liquid

Crystal

Keerti Choudhary

30

8. Li 2SO4-Li 2O-P2O5 Ionic Glass Dispersed with [Bmim] [PF6] Ionic Liquid: Electrical Transport and Thermal Stability Investigations

Munesh Rathore

31

9. Thin Film studies on disc shaped tethered with rod like liquid crystal molecules

C. Karthik 32

10. Opening Profile of DNA Unzipping: Eye & Y-shape Phase Diagrams Amar Singh 33 11. One Dimensional Schrodinger-Poisson Solver Using Finite Difference

Method Surender Pratap

34

12. Magnetic superatom in MgnCo clusters (n=1-10): A first principle prediction

Ravi Trivedi 35

13. Landau-Fock-Darwin Confinement in two-Dimensional Space with Conical Disclination: A Thermodynamic Study

Tridev Mishra 36

** Serial number is the poster number also.


ORAL

PRESENTATIONS


Fluorescence Quenching of Quinine Sulfate Dication: an indicator for sensing Chloride ion

in Ionic and Neutral Micellar Environments

Sunita Joshi and D. D. Pant Department of Physics, Birla Institute of Technology & Science, Pilani (India)

[email protected]

Fluorescence quenching of Quinine sulfate dication (QSD) by chloride-ion (Cl-) in

micellar environments of anionic, sodium dodecyl sulfate (SDS), cationic,

cetyltrimethylammonium bromide (CTAB) and neutral, triton X-100 (TX-100) in aqueous phase

has been investigated by time-resolved and steady- state fluorescence measurements. The

quenching follows linear Stern-Volmer relation in micellar solutions and is dynamic in nature. A

significant reduction of quenching of fluorescence of QSD takes place in SDS micellar solution;

a moderate reduction takes place in CTAB and almost no change in TX-100 micelles when

compared with the quenching of QSD by Cl- in bulk water solution. In SDS micelles, the decay

becomes multi-exponential with an additional lifetime component and has been attributed to a

fraction of QSD molecules residing at the water-micelle interface. The probe molecules at

interface are protected from interaction with Cl-, consequently, a significant reduction in

fluorescence quenching of QSD in SDS micelles. The present study reveals that the chloride

sensing ability of QSD in biological media might get affected.

mailto:[email protected]


Variants of Hardness Potential: Development and Applications

Rituparna Bhattacharjee and Ram Kinkar Roy Department of Chemistry, Birla Institute of Technology & Science, Pilani (India)

[email protected]

A simple method to obtain hardness potential (as defined by Parr and Gazquez, J. Phys.

Chem., 1993, 97, 3939) is presented. Use of hardness potential formally resolves the N-

dependence (N is no. of electrons of the system) problem of local hardness. It is shown that the

hardness potential has the ability to describe the intra- as well as intermolecular reactivity

sequence of a series of chemical systems. The corresponding electrophilic [)(kh ] and

nucleophilic [ )(kh ] variants of the hardness potential are also developed (Saha et al. J. Comp.

Chem. 2013, 34, 662). It is also shown that these two variants of the hardness potential leads to

the right and left derivatives of Fukui potential (as introduced by Berkowitz, J. Am. Chem. Soc.,

1987,109, 4823). The relative contribution of the sum of kinetic

3/2)(9

10rCF and exchange

energy

3/1)(9

4rCX terms to that of the electronic part of the molecular electrostatic potential

[ )(rVel ] in the variants of Hardness Potential is investigated to assess the proposed definition of

)]()([)( 1 kVkVkh Nel

Nel and )]()([)( 1 kVkVkh N

elN

el (Bhattacharjee et al. J. Phys.

Chem A, 2013, 117, 11528).



A Density Functional Reactivity Theory Based Approach to Understand the Interaction between Aun (n = 3-6) Metal Clusters and Nucleobases

Amrit Sarmah and Ram Kinkar Roy Department of Chemistry, Birla Institute of Technology & Science, Pilani (India)

[email protected], [email protected]

It is important to understand the interaction of biological macromolecule such as DNA with a

particular metal surface because the restricted movement of nucleobases on the inorganic surface

modulates the characteristic electronic properties of the metal clusters to a considerable extent.

Various thermodynamic and kinetic aspects of the metal cluster-nucleobase interaction along

with the charge transfer process is investigated using Density Functional Reactivity Theory

(DFRT) based CDASE scheme. An extensive conventional ab-initio study is performed to

analyze more details about the other critical factors associated with the stable complex formation

between Aun cluster and nucleobases. It is expected that the tunable electronic properties of the

combined system (nucleobase-Aun cluster) is extremely useful for designing biological logic gate

on the next generation biosensors. The interaction trend of nucleobases with Aun clusters found

to follow the order G > A > C > T > U. It is also observed that Watson-Crick base pair GC

interaction with Aun cluster is both thermodynamically and kinetically more preferable in

comparison to that of the AT pair. We have obtained a precise correlation between the findings

of present study with earlier reported literature.




Surface Plasmon Resonance Studies of Stearic Acid and Octadecanethiol Systems

Devanarayanan VP, Raj Kumar Gupta, V. Manjula Devi

Department of Physics, Birla Institute of Technology & Science, Pilani (India)

[email protected]

Surface Plasmons are the electronic oscillations at the metal-dielectric interface. Due to the role

of refractive index of dielectric layer in coupling condition of surface plasmons to the evanescent

waves of prism, the method is powerful to detect various chemical forms. We have developed a

surface plasmon resonance sensor in Kretschman geometry which is calibrated using the stearic

acid (common fatty acid) system. We have developed ultrathin films of stearic acid(C18H36O2) as

well as Octadecanethiol (C18H37SH;ODT) using various techniques and studied the SPR

characteristics. We found the surface plasmon resonance angular shift for stearic acid is less

than that of the ODT.



Thermal Properties of a Particle Confined to a Parabolic Quantum Well in Two-

Dimensional Space with Conical Disclination

Tridev Mishra, Tapomoy Guha Sarkar, Jayendra Nath Bandyopadhyay


[email protected]

The thermodynamic properties of a system, comprising of a spinless non-interacting charged

particle in the presence of an external magnetic field and confined in a parabolic quantum well

are studied. The focus has been on the effects of a topological defect, of the form of conical

disclination, with regard to the thermal properties of the system. We have obtained the

modifications to the traditional Landau-Fock-Darwin spectrum in the presence of conical

disclination. The effect of the conical kink on the degeneracy structure of the energy levels is

investigated. The canonical formalism is used to compute thermodynamic variables like entropy,

internal energy and specific heat. The study shows interplay between magnetic field, temperature

and the degree of conicity. The problem sets two scales for temperature corresponding to the

frequency of the confining potential and the cyclotron frequency of external magnetic field. The

kink parameter is found to affect the quantitative behaviour of the thermodynamic quantities. It

plays a crucial role in the competition between the external magnetic field and temperature in

fixing the values of the thermal response functions. This study provides an important motivation

for studying similar systems, however with non trivial interactions in the presence of topological

defects.



Shell Magnetism of Chromium Doped Germanium Superatom

Kapil Dhaka and Debashis Bandyopadhyay


[email protected]

It has been demonstrated that in a specific composition and size of a particular nanoclusters can

behavelike an elemental atom in the periodic table and hence can be chosen as superatoms [1-3].

According to the consequence of shell models some of the magic clusters can mimic chemical

properties of an elemental atoms. Following these, we have studied the structural, electronic and

magnetic properties for Cr@Gen (n=1 to 20) nanoclusters using density functional based first-

principles electronic structure calculations. From the study of the HOMO-LUMO gap, 2nd order

change in energy and adiabatic spin excitation energy in the complete range of the series of

Cr@Gen (n=1-20), the composition Cr@Ge10in quintet spin state is found most stable both

chemically as well as thermodynamically. The present study reports that the first and second

ionization potential (IP) of such superatom is 7.41eV and 10.93eV respectively. These values are

very close to the 1st and 2nd IPs of Ca and Sr, which are 6.11 eV and11.87 eV respectively.

References :-

1. Lin Zhu, Meichun Qian, and Shiv N. Khanna, J. Chem. Phys. 139, 064306 (2013)

2. Xinxing Zhang, Yi Wang, Haopeng Wang, Alane Lim, Gerd Gantefoer , Kit H. Bowen, J. Ulises

Reveles, and Shiv N. Khanna, J. Am. Chem. Soc.,135 (12), pp 4856–4861 (2013)

3. J.U. Reveles, P.A. Clayborne, A.C. Reber, S.N. Khanna, K. Pradhan, P. Sen, M.R. Pederson. Nature

Chemistry 1 310 (2009).


http://pubs.acs.org/action/doSearch?action=search&author=Zhang%2C+X&qsSearchArea=author

http://pubs.acs.org/action/doSearch?action=search&author=Wang%2C+Y&qsSearchArea=author

http://pubs.acs.org/action/doSearch?action=search&author=Wang%2C+H&qsSearchArea=author

http://pubs.acs.org/action/doSearch?action=search&author=Lim%2C+A&qsSearchArea=author

http://pubs.acs.org/action/doSearch?action=search&author=Gantefoer%2C+G&qsSearchArea=author

http://pubs.acs.org/action/doSearch?action=search&author=Bowen%2C+K+H&qsSearchArea=author

http://pubs.acs.org/action/doSearch?action=search&author=Reveles%2C+J+U&qsSearchArea=author

http://pubs.acs.org/action/doSearch?action=search&author=Reveles%2C+J+U&qsSearchArea=author

http://pubs.acs.org/action/doSearch?action=search&author=Khanna%2C+S+N&qsSearchArea=author


Effect of the Functionalized Carbon Nanotubes on the Physical Properties of Nematic

Liquid Crystal

Jitendra Kumar and Manjuladevi. V


[email protected]

We have investigated the effect of Functionalized carbon nanotube(FCNT) on the threshold

voltage and dielectric properties for pure nematic liquid crystal and CNT doped nematic liquid

crystal(NLC). The LCs were doped with two different FCNT (Octadecylamine functionalized

CNT (ODACNT) and acid functionalized CNT (AFCNT). It was found that doping the FCNT

into LC led to decrease in the threshold voltage compared to that of pure liquid crystal and

dielectric anisotropy is enhanced. The dielectric measurements reveal that relaxation frequency

for the doped sample has been shifted to the higher value compared to that of pure LC. The

conductance measurement using Atomic Force Microscopy (AFM) reveal the presence of FCNT

at the alignment layer.


Interaction of DNA and Langmuir Blodgett film of dioctadecyl ammonium bromide using

QCM

Monika Poonia and Raj Kumar Gupta*


[email protected]

We studied the interaction of DNA with a highly ordered functional ultrathin layer of cationic

surfactant, dioctadecyl ammonium bromide (DOAB). The ultrathin film of DOAB is fabricated

onto the pre-treated quartz crystal wafers using Langmuir Blodgett (LB) technique. The solution

of DNA in phosphate buffer saline (PBS) is injected through flow cell in a quartz crystal

microbalance (QCM) loaded with the functional ultrathin film. We also observed the aggregation

of DNA over the DOAB layer using atomic force microscope (AFM). The AFM image indicates

the trapping of DNA over the DOAB layer. Such trapping of DNA play an important role in the

field of genomics.



Morphological and Electrical Characterization of Thin Film of TiO 2 Nanoparticles

Keerti Choudhary and Manjuladevi V.


[email protected]

TiO2 nanoparticles can be employed in the fabrication of numerous photovoltaic devices. In the

present work, the thin film of TiO2 nanoparticles were deposited on gold deposited substrate by

spin coating method. The morphology of the TiO2 nanoparticles were characterized using atomic

force microscopy. We recorded the current-voltage (I-V) characteristic curve of the film

deposited onto gold electrodes. The change in band gap of the film was studied as a function of

temperature. The effect of visible light on the film was also studied.


Effect of Conditional Glass Former Variation on Electrical Transport in Li2O-P2O5 Glassy and

Glass-Ceramic Ionic System

Munesh Rathore and Anshuman Dalvi


[email protected]

Giving emphasis to electrical transport in the thermally unstable region, a conditional glass

former based system 50Li2O-(50-x)P2O5-xMoO3 is investigated. The glass forming region of this

system is found to be limited upto (x ≤ 15 mol %). However in this narrow region, the electrical

conductivity in case of glass as well as glass-ceramics exhibits significant increase with MoO3

content and found to be maximum for x = 15 mol %. The behavior of conductivity during

crystallization is nicely correlated with structural changes. It is revealed from conductivity

cycles, X-ray diffraction, scanning electron microscopy (SEM) and differential scanning

Calorimetry that addition of MoO3 suppresses the crystallization and improves the thermal

stability. Therefore, for samples with 15 mol % of MoO3, the conductivity of glass and glass-

ceramic is found to be comparable. SEM investigations suggest existence of tiny nano-

crystallites well separated by glass tissues for higher MoO3 content samples. Electronic

conductivity in these samples suggests phonon assisted polaron hopping. Further samples are

predominatly ionic in nature. The samples are found to be stable under battery conditions.



Surface Studies on a Novel Discotic Liquid Crystalline Molecule C. Karthik and Raj Kumar Gupta


[email protected]

In recent past, researchers have found immense interest in the disk shaped liquid crystals due to

their fascinating electro-optical properties. We have studied the surface manometry and surface

morphology of Langmuir-Blodgett films of Tricycloquinazoline (TCQ) based molecule tethered

with six ketone groups using Atomic Force Microscopy and spectroscopy. Using infrared

spectroscopy, it has been found that the transition dipole moment of TCQ molecule is planar to

the surface.



Synthesis of ZnO/Au and ZnO/Ag nanoparticles and their photocatalytic application using UV and visible light

$Pragati Fageria, #Subhashis Gangopadhyay and $Surojit Pande $ Department of Chemistry, Birla Institute of Technology & Science, Pilani (India)

#Department of Physics, Birla Institute of Technology & Science, Pilani (India) [email protected]

Here, we report the low temperature gram level synthesis of ZnO/Au and ZnO/Ag nanoparticles

using cetyltrimethylammoniumbromide (CTAB) surfactant as a stabilizer. Initially, pure ZnO

nanoparticles were synthesized and then Au and Ag were deposited on ZnO surface using

hydrazine hydrate as reducing agent. The information about the sample crystallinity, structure

and surface morphology were assessed by UV-VIS spectroscopy, photoluminescence, X-ray

Diffraction, X-ray photoelectron spectroscopy, EDS, SEM, and TEM techniques. The influences

of the deposited metals (Au and Ag) on the surface of ZnO have been emphasized by applying

the as-synthesized nanoparticles in dye degradation under illumination of UV and visible light.

Photocatalytic performances of bare ZnO, ZnO/Ag, and ZnO/Au have been studied thoroughly.

The photocatalytic results reveal that the incorporation of noble metals not only enhance the

catalytic efficiency but also promotes the separation of photogenerated electron and hole pairs.

To investigate the charge carrier species, which involved in the degradation of dye we performed

scavenging experiment using different scavenger. It indicates that the holes in valence band play

major role when catalysis performed under visible light but the case is quite different under UV-

light, where, both the holes and hydroxyl radicals play important role in degradation of the dye

molecule.

Reference

1. Hui Zhang, Deren Yang, Yujie Ji, Xiangyang Ma, Jin Xu, and Duanlin Que, J. Phys. Chem. B, 2004,108, 3955-

3958.

2. Jun Geng, Guang-Hui Song, Xiang-Dong Jia, Fang-Fang Cheng, and Jun-Jie Zhu, J. Phys. Chem. C, 2012, 116,

4517-4525.

3. Nayane Udawatte, Myeongsoon Lee, Junhyung Kim, and Dongil Lee, ACS Appl. Mater. Interfaces, 2011, 3,

4531-4538.

4. Jian Xu, Yonggang Chang, Yunyan Zhang, Shiyu Ma, Yi Qu, Chengtian Xu, Applied Surface Science, 2008, 255,

1996- 1999.

5. Nan Zhang, Siqi Liu, Xianzhi Fu, and Yi-Jun Xu, J. Phys. Chem. C, 2011, 115, 9136–9145.


Experimental and Theoretical studies of 'Ship-in-a-Bottle' Ni(II) Schiff base Complexes in

Zeolite Y

Archana Choudhary1, Saumi Ray1 and Bidisa Das2 1Department of Chemistry, Birla Institute of Technology & Science, Pilani (India)

2Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032.

[email protected]

It is observed that square planar Ni(II)–Schiff base complexes of general formula [Ni(L)2], (L:N,

Ń-bis(salicylidene)ethylenediamine, and N, Ń-bis(5-bromo salicylidene)ethylenediamine) when

encapsulated in a supercage of zeolite Y, the bulky guest complex adopt a non-planar geometry.

Detailed comparative characterization is carried out to understand the structural change of the

guest complex due to steric and electronic effects of the host framework while keeping the

integrity of framework intact after encapsulation. UV-Vis spectroscopic studies of encapsulated

and ‘neat’ complex show significant blue shift in d-d transition after encapsulation and the

diamagnetic 'neat' complex exhibits paramagnetism after encapsulation. DFT studies of Ni(II)–

Schiff base complexes have been carried out for neat and encapsulated form and the UV-Vis

spectra are simulated using TD-DFT to understand the observed spectra in full details.


Determination of Channel Electron Density of a Nano-MOSFET using Quantum and Semi-

classical Methods

Surender Pratap and Niladri Sarkar


[email protected]

Study of the electronic transport in Nano-Scale Devices is extremely important for understanding the working principles of futuristic devices. The variation of the electron density in the channel of a Nano-MOSFET will dictate its I-V characteristics. . For Nano-scale devices, the electron density can be calculated from diagonal elements of the density matrix. Another approach will be the semi-classical approach where the electron density, n, is given as

Tk

zUEF

h

kTmn

B

cnD

2/1

2/3

23

24

where 2/1F is the Fermi-Dirac integral. Effect of the size quantization is very well reflected when

we calculate the electron density using density matrix. However, when we increase the channel thickness, the result obtained by density matrix calculation matches with the semi-classical approach. The following figure shows the generic device(Dual Gate MOS Capacitor) which is used for our calculations.



Synthesis, Characterization and Catalytic Applications of Palladium Complex for C-C Coupling Reactions

Pankaj Nehra, Vaishali Saini, S. C. Sivasubramanian*1 Bharti Khungar*2

Department of Chemistry, Birla Institute of Technology & Science, Pilani (India) *[email protected], *[email protected]

Transition metal complexes have been employed as catalyst for varied organic transformations.

The C-C bond forming reactions are very effective and important reactions in organic synthesis

[1]. Palladium-catalyzed cross-coupling reactions have significant contribution in organic

synthesis to build aryl−aryl bonds [2]. An intriguing aspect of palladium catalysis is its broad

synthetic applications that has played pivotal task in the synthesis of fine chemicals and

advanced functional materials [3, 4]. We have devised a novel route to synthesize an air stable,

water soluble and efficient Schiff base palladium complex. The complex was well characterized

by NMR, Mass, FT-IR, UV-visible spectroscopy, time resolved spectroscopy and powdered X-

ray diffraction and used as a catalyst for the C-C cross-coupling reactions in water. Good to

excellent yields with estimable turn over numbers and turn over frequencies were achieved using

modest mole percent of the catalyst. In addition, the catalyst can easily be reused and recycled

for more than six steps without much loss in reactivity, exhibiting an example of sustainable and

green methodology

References:

1. S. Wang Q. and Qian, H. Gong, Org. Lett. 14, 2012, 3352.

2. J. Ruan and J. Xiao, Acc. Chem. Res., 2011, 44, 614-626.

3. C.-H. Lu and F.-C. Chang, ACS Catal., 2011, 1, 48-488.

4. A. B. Dounay and L. E. Overman, Chem. Rev., 2003, 103, 2945-2963; Overman, L. E.; Rosen, M. D.

Angew. Chem., Int. Ed. 2000, 39, 4596.

mailto:*[email protected]

mailto:*[email protected]


Figure: The figure in left shows the variation critical force vs chain length and figure in right shows the effect of random and equal force at different sites.

DNA Unzipping due to Random Force

Amar Singh and Navin Singh


[email protected]

We investigate the mechanical unzipping of double-stranded DNA (dsDNA) by pulling two

strands in opposite directions in the constant force ensemble. The force is applied on randomly

selected sites along the chain and hence we calculate the force required to unzip the chain

(critical force, Fc). Using a two state model, we investigate the effect of the distribution of force

on the unzipping phenomenon and found that there is a critical region over which the force

applied at a point has no effect. The critical force is found to depend on the chain length as well

on the location of the applied force.



Density functional study of Hydrogen storage in small MgnCo clusters: A future energy

solutions

Ravi Trivedi, Kapil Dhaka and Debashis Bandyopadhyay


[email protected]

The present study reports the possibility of using Mg-Co hybrid nanoclusters as hydrogen

storage. It is well known that Magnesium and Magnesium based alloys are very much effective

as high hydrogen storage. Moreover, these alloys are light weight, cost effective and hence the

most promising candidates for hydrogen storage [1-2]. Because of the physical nature of

hydrogen, it is difficult to store it in a large quantity without taking up a significant amount of

space. Therefore search for the safe, reliable and cost effective hydrogen storage elements is one

of the main challenge in this field. But many metals and their alloys are capable of absorbing

large amounts of hydrogen to form metal hydride. So it is important to understand the interaction

of hydrogen with these materials. In general at the beginning metal hydride formation initiates by

dissociative chemisorptions of H2 on the metal surface and then H atom diffusion starts into the

crystal lattice in case of bulk systems [3-4]. On the other hand, it has been found that small sized

transition metal clusters improves the absorption process. Clusters are having high surface to

volume ratio which makes available surface for chemisorption of hydrogen more than the bulk.

Therefore in the present report structure, stability and reactivity of MgnCo (n=1-10) clusters with

or without hydrogen adsorption were studied using density functional theory. Binding energy,

chemisorptions, dissociation energies, reaction path, dipole moment and HOMO-LUMO gap

have been calculated and presented. The information gained can contribute to the design of novel

nanoclusters materials for hydrogen storage.

References

1. Hydrogen storage in magnesium based alloys, Waste-enviorment.vin.bg.ac.rs, J.Garbovic Novakovic, Tanja Brdaric, N. Novakovic, S. Mentus, pdf (2009)

2. Materials for hydrogen storage: current research trends and perspectives Annemieke W. C. van den Berg and Carlos Otero Area, ChemComm (2007)

3. Trends in hydride formation energies for magnesium-3d transition metal alloys, Journal of Alloys and Compound 386 (2005) 1–7

4. G walker, Solid state hydrogen storage: Materials and chemistry, Elsevier (2004)



Organocatalytic approach towards the synthesis five-membered nitrogen heterocycles

Nisar Ahmad Mir, and Indresh Kumar

Department of Chemistry, Birla Institute of Technology & Science, Pilani 333031 (Rajasthan)

[email protected]

Pyrrolidines are the most important and versatile moiety found in natural products,

pharmaceuticals, agrochemicals and other synthetic compounds [1, 2]. In continuation of our

interest in organocatalyzed reactions [3], using linear dicarbonyl compounds as donor- acceptor

precursors, presently we developed an efficient organocatalytic method using succinaldehyde as

1, 3- carbon dipole and imines for the synthesis of 2,3- disubstituted pyrrolidines in high yields

(upto 78%) and excellent enantioselectivity (upto > 99%) [4]. The present idea of 1,3- carbon

dipole is very compatible and even more greener as compare to the only two methods known

earlier [4,5] and this method can be further utilized for the synthesis of some small molecule

natural products. Further after synthesizing the series of compounds we characterised these

compounds using various spectroscopic techniques such as 1H NMR, 13C NMR, mass

spectroscopy, optical rotation, HPLC and to assign relative and absolute configuration we

characterize one of the compound by X-ray crystallographic technique as shown in (figure 1).

Figure 1: 1H NMR and X-ray Structures of one of the compound

Details of this work will be presented here (scheme 1).

Scheme 1: Insitu generation of 1, 3- carbon dipole from succinaldehyde and application in pyrrolidine synthesis



POSTER PRESENTATIONS


Photophysics of Quinine Sulphate Dication in Micellar Environments

Sunita Joshi and D. D. Pant


[email protected]

Steady state absorption and fluorescence spectral studies have been carried out for quinine

sulphate dication (QSD) in cationic cetyltrimethylammonium bromide (CTAB), anionic sodium

dodecylsulphate (SDS) and neutral triton X-100 (TX100) surfactants at concentrations above and

below critical micelle concentrations (c.m.c.) in aqueous phase. Edge excitation red shift (EERS)

in fluorescence maximum of QSD has been observed in all the surfactant solutions studied. The

magnitude of observed EERS is less in anionic SDS surfactant solution compared to the EERS in

CTAB and TX100 surfactants. The magnitude of EERS in CTAB and TX100 is almost the same

as in bulk water solution. The EERS has been ascribed in terms of solvent relaxation process. In

CTAB surfactant solution a continuous decrease in fluorescence intensity has been observed with

increase in surfactant concentration and is due to Stern –Volmer quenching. At premicellar

concentrations of SDS, the decrease in absorbance and appearance of an extra fluorescence band

at lower wavelengths are attributed to the ion-pair formation between QSD molecules and

surfactant monomers. At postmicellar concentrations the red shift in fluorescence spectrum and

increase in quantum yield are attributed to the incorporation of solute molecules to micelles.

Compared to the magnitude of edge excitation red shift (EERS) in bulk water solution of QSD,

the magnitude of EERS is less at higher concentrations of SDS due to heterogeneous restricted

motion of solvent molecules, whereas, at lower concentrations of SDS, a large shift in

fluorescence is observed on excitation at the red edge of absorption spectrum and this is

explained in terms of distribution of ion pairs of different energies in the ground state.



Effect of Nanosize Micelles of Ionic and Neutral Surfactants on the Photophysics of

Protonated 6-Methoxyquinoline: Time-resolved Fluorescence Study

Tej Varma Y, Sunita Joshi and D. D. Pant


[email protected]

The excited state dynamic studies have been carried out to investigate the effects of micellar

surface charge on the photophysics of protonated 6-methoxyquinoline (6MQ+) in anionic,

sodium dodecylsulphate (SDS), cationic, cetyltrimethylammonium bromide (CTAB) and neutral,

triton X-100 (TX100) surfactant at premicellar, micellar and postmicellar concentrations in

aqueous phase at room temperature. At premicellar concentration of SDS, there is a slight

decrease in emission intensity and at micellar and postmicellar concentrations increase in

emission intensity and blue shift of fluorescence spectrum and slight increase in quantum yield

are attributed to incorporation of solute molecule to micelles. Edge excitation red shift (EERS) in

fluorescence maximum of 6MQ+ has been observed in all the surfactant solutions studied. The

EERS has been ascribed in terms of solvent relaxation process. In SDS surfactant system, due to

heterogeneous restricted motion of solvent molecules, the solvent viscosity increases which

results in an increase in net magnitude of EERS and fluorescence decay components fit in multi

exponentials. The location of the probe molecule in micellar systems is justified by a variety of

spectral parameters such as refractive index, dielectric constant, ET(30), EERS, average

fluorescence decay time, radiative and non radiative rate constants, and rotational relaxation

time.



Surface Plasmon Resonance studies of Langmuir-Blodgett Films of Stearic Acid

Devanarayanan VP, Raj Kumar Gupta, V. Manjula Devi


[email protected]

Stearic acid is one of the commonly studied fatty acid. It exhibits interesting behavior on

surfaces. We have developed a surface plasmon resonance (SPR) instrument in the kretschman

configuration. Single layers of Langmuir-Blodgett (LB) films of stearic acid(SA) and films for

different concentrations of SA in chloroform were analyzed using our SPR setup. We find

interesting changes in SPR angle for the LB film and film deposited from solution.



Magnetic behavior in Cr2@Gen (1≤n≤12) Clusters: A Density Functional Investigation

Kapil Dhaka and Debashis Bandyopadhyay


[email protected]

With an aim to hold the magnetic moment of Cr in Cr2@Gennanoclusters,we have investigated

the structure and magnetic properties of pure Ge clusters doped with Cr dimer to produce

Cr2@Gen clusters. These kinds of nanoclusters have potential applications because of their high

magnetic moment. As the first step of calculation, geometrical optimizations of the nanoclusters

have been done. The optimized geometries have been used to calculate the average binding

energy per atom (BE), HOMO-LUMO gap and relative stability of the clusters. These

parameters have been demonstrated as structural and electronic properties of the clusters. Gap

between highest occupied molecular orbital and lowest unoccupied molecular orbital indicate

cluster to be a potential motif for generating magnetic cluster assembled materials. Based on

these values a comparative study on different sized clusters has been done in order to understand

the growth behaviour, electronic and magnetic properties of Cr2@Gen nanoclusters.


Temperature Dependent Electro-optic and Dielectric Properties of CdSe QD’s Doped

Nematic Liquid Crystal

Jitendra Kumar and Manjuladevi. V


[email protected]

We have studied the electro-optic and dielectric properties of cadmium selenide Quantum Dots

(CdSe QDs) doped nematic liquid crystal. The nematic liquid crystal was doped with different

concentrations of semiconducting quantum dots (QDs). The doped sample is found to have a

lower threshold voltage than that of pure NLC. The dielectric permittivity is estimated as a

function of temperature for both planar and homeotropic cells in order to find out dielectric

anisotropy. It was found that doping QDs led to increase in dielectric anisotropy in comparison

with that of pure liquid crystal. The result showed that the addition of QDs to NLC molecules

provide a way to improve the performance of LC based devices. The N-I transition temperature

for doped sample is comparable to that of pure LC.



Study on Detection of Contamination in Water using Quartz Crystal Microbalance

Monika Poonia and Raj Kumar Gupta


[email protected]

In recent years, there has been a rapid growth in the number of scientific reports in which the

quartz crystal microbalance (QCM) technique has played a key role for sensing applications. In

this work, we have detected the contaminations in water using QCM. The water with different

impurities is injected through a flow cell in a QCM. We found that resonance frequency of the

crystal decreases with increasing the impurity in water. We have investigated the temperature

dependent response of QCM for different water.



Langmuir- Blodgett films of Stearic acid - Aligning agent for Liquid Crystal

Keerti Choudhary and Manjuladevi V.


[email protected]

Stearic acid, because of its bifunctional character with a polar head group which can be attached

to metal ions and nonpolar chain, that is soluble in organic solvent finds use in many industrial

application. We formed the Langmuir monolayer of stearic acid at the air -water interface. We

have deposited single and multi layer of film on substrates at different pressures. We prepared

liquid crystal cell using such substrates. We found these cells exhibit tendency to align the

liquid crystal in planar orientation. We found that the liquid crystal alignment improves in cells

prepared with substrates deposited at higher pressures. We propose that stearic acid monolayer

can be used as an aligning agent for liquid crystals.



Li 2SO4-Li 2O-P2O5 Ionic Glass Dispersed with [Bmim] [PF6] Ionic Liquid: Electrical Transport and Thermal Stability Investigations

Munesh Rathore1, Anshuman Dalvi1 and Anil Kumar2

1 Department of Physics, Birla Institute of Technology & Science, Pilani (India) 2 Department of Chemistry, Birla Institute of Technology & Science, Pilani (India)

[email protected]

Li+ ion conducting oxide glasses and glass-ceramics are the promising candidates for future solid

state ionic devices. However, their application is so far limited because of their low electrical

conductivity near room temperature. Recently, there has been interesting efforts of preparation of

ionic liquid-glass composites that exhibit high ionic conductivity at room temperature A fast

ionic composite is prepared by dispersion of Ionic liquid [Bmim][PF6] in Li2SO4-Li 2O-P2O5

glassy matrix by mixing through grinding. Amorphous/glassy nature of the samples is confirmed

by X-Ray diffraction (XRD). Surprisingly, the electrical conductivity of the samples is found to

be increasing by ~2 orders of magnitude and exhibits typical Arrhenius behavior with low

activation energy. DC polarization and impedance spectroscopy measurements suggest that

samples are essentially ionic in nature. The conductivity isotherms were also obtained at

different temperatures (T < 100 οC) and found to be appreciably stable at least for ~ 10 days.

Cyclic voltammograms on the systems are also obtained on cell of the type C|composite|C that

confirm an electrochemical stability window of at least 4 volts.



Thin Film studies on disc shaped tethered with rod like liquid crystal molecules

C. Karthik and Raj Kumar Gupta


[email protected]

Tricycloquinazoline (TCQ) acts as a potential core for designing interesting disk-shaped liquid crystals.

The liquid crystals composed of TCQ core exhibit interesting mesophases. We have studied the Langmuir

Blodgett (LB) films of such disk-shaped liquid crystals tethered with six cyano bi-phenyl groups

deposited at various target surface pressures using atomic force microscope. The LB films deposited at

various pressures revealed interesting topographical features.



Opening Profile of DNA Unzipping: Eye & Y-shape Phase Diagrams

Amar Singh and Navin Singh


[email protected]

We investigate the opening profile of a double stranded DNA (dsDNA) that is pulled from an

end or mid of the chain. We consider a homogeneous chain (all base pairs are of same kind) and

pulled the chain in constant extension ensemble (CEE). In CEE, the separation between the end

base pair of one of the ends in the dsDNA molecule is kept fixed. Average force needed to keep

this separation is measured by evaluating the change in free energy in displacing the base pair

from equilibrium position. We calculate the probability of opening of a pair and investigate the

opening of complete chain. The density plots clearly show the formation of Eye & Y-shape of

the transition from close to open state of DNA.

Figure: The figure in left shows Y-shape opening of DNA unzipping while figure in right shows Eye-shape opening when the chain pulled from the mid.



One Dimensional Schrodinger-Poisson Solver Using Finite Difference Method

Surender Pratap and Niladri Sarkar


[email protected]

We are modeling a dual gate MOS capacitor with channel thickness of the order of few

nanometers.The problem has quantum confinement along z-axes and we apply periodic boundary

condition in the x-y plane. Study of the electronic transport in Nano-Scale Devices is extremely

important for understanding the working principles of futuristic devices. The variation of the

electron density in the channel of a Nano-MOSFET will dictate its I-V characteristics.This is a

good approximation as the channel length and width dimensions are much larger than its

thickness.The Schrodinger equation and the Poisson equations are solved self consistently by

using Finite-Difference method.



Magnetic superatom in MgnCo clusters (n=1-10): A first principle prediction

Ravi Trivedi and Debashis Bandyopadhyay


[email protected]

The present study illustrates the formation of magnetic superatom in MgnCo (n= 1-10) cluster

based on a gradient corrected density functional approach. Co doped Mg8 cluster with 33 valence

electrons has filled 1S2,1P6,1D10,2S2….. Shells, making it highly stable and due to 4 unpaired

electrons breeding the magnetic moment. The newly discovered clusters, leading to the shell

model show enhanced stability. These stable clusters can mimic the chemical behavior of atoms

in the periodic table [1-4]. It has been investigated that group IIA elements (eg. Mgn, Can and

Srn) are the ideal elements and host for design super atom. Doping of transition metal into these

clusters induced exchange splitting energy of D orbital’s, due to the hybridization between the d

orbital’s of TM atom and D orbitals of the whole system. The ionization potential of such

superatom is 5.37e v, which is similar to Li and Lu atom group which have IP around of 5.39 and

5.42ev. As an application point of view we can say that these new clusters used to make

molecular electronic devices for computers with large memory storage.

References

1. Bergeron, D. E.; Castleman, A. W., Jr.; Morisato, T.; Khanna, S. N. Science 2004, 304, 84.

2. Bergeron, D. E.; Roach, P. J.; Castleman, A. W., Jr.; Jones, N. O.; Khanna, S. N. Science 2005, 307,

231.

3. Jones, N. O.; Reveles, J. U.; Khanna, S. N.; Bergeron, D. E.; Roach, P. J.; Castleman, A. W., Jr. J.

Chem. Phys. 2006, 124, 154311.

4. Bergeron, D. E.; Castleman, A. W.; Morisato, T.; Khanna, S. N. J. Chem. Phys. 2004, 121, 10456



Landau-Fock-Darwin Confinement in two-Dimensional Space with Conical Disclination:

A Thermodynamic Study

Tridev Mishra, Tapomoy Guha Sarkar, and Jayendra Nath Bandyopadhyay


[email protected]

The thermodynamic properties of a system, comprising of a spinless non-interacting charged

particle in the presence of an external magnetic field and confined in a parabolic quantum well

are studied. The focus has been on the effects of a topological defect, of the form of conical

disclination, with regard to the thermal properties of the system. We have obtained the

modifications to the traditional Landau-Fock-Darwin spectrum in the presence of conical

disclination. The canonical formalism is used to compute thermodynamic variables like entropy,

internal energy and specific heat. The study shows the interplay between magnetic field,

temperature and the degree of conicity. The kink parameter is found to affect the quantitative

behaviour of the thermodynamic quantities. It plays a crucial role in the competition between the

external magnetic field and temperature in fixing the values of the thermal response functions.


schedule for research scholar day 2014schedule for research scholar day 2014 venue: 5104...

Documents