ultrafast processes in molecules

Ultrafast processes in moleculesUltrafast processes in molecules

Mario Barbattibarbatti@kofo.mpg.de

X – Case studies of dynamics simulations

Case 1: Aminopyrimidine

Aminopyrimidine

• Barbatti and Lischka, J Phys Chem A 111, 2852 (2007)

Can the Nonadiabatic Photodynamics of Aminopyrimidine Be a Model for the Ultrafast Deactivation of Adenine?

No!

Restricted aminopyrimidine

• Barbatti and Lischka, J Phys Chem A 111, 2852 (2007)

Can the Nonadiabatic Photodynamics of Aminopyrimidine Be a Model for the Ultrafast Deactivation of Adenine?

Hum, Maybe !?

1000 amu

Surface hopping: dynamics example

• Nachtigallova, Zeleny, Ruckenbauer, Muller, Barbatti, Hobza, Lischka, JACS 132, 8261 (2010)

Case 2: Azobenzene

Phototrigger

Dynamics

• Pederzoli, Pittner, Barbatti, Lischka, J Phys Chem A 115, 11136 (2011)

Dihedral evolution

Chirality

Biased initial conditions

Initial velocities biased towards positive projection of the clockwise direction

• Pederzoli, Pittner, Barbatti, Lischka, J Phys Chem A 115, 11136 (2011)

Case 3: Cr(CO)6

Cr(CO)6 method assessment

CrCOTheoretical x Experimental deviations in

transition energies and intensities

CC

• Crespo-Otero, Barbatti, J Chem Phys 134, 164305 (2011)

Cr(CO)6 photochemistry

Time constant (fs)

Simulation Experimental

τ1 19 21 ± 1

τ2 41 43 ± 3

τIC 148 68 ± 6

dtet 1 d et t 2 3d et t IC

CrCO

[Cr(CO)6]*

[Cr(CO)5• • •CO]*

[Cr(CO)5]*+CO

Cr(CO)5+CO

0 τ1 τ2 τIC

I II

III

MLCT

MC

Time

Ener

gy

• Kosma, Trushin, Fuss, Schmid, Schneider, PCCP 12, 13197 (2010)• Crespo-Otero, Barbatti, J Chem Phys 134, 164305 (2011)

Case 4: Formamide

Formamide photolysis

• Lundell, Krajewska, Rasanen, J Phys Chem A 102, 6643 (1998)

O

NH2

193 nmGas phase

193 nmAr matrix

193 nmXe matrix

NH3 ••• CO

NH2 + COH

H2 + NCOH

Formamide in Ar matrix

• Eckert-Maksic, Vazdar, Ruckenbauer, Barbatti, Muller, Lischka, PCCP 12, 12719 (2010)

QM: formamide• CASSCF(10,8)/6-31G*

MM: Ar matrix• 661 atoms• 18 K• OPLSAA force field

Dynamics• 100 trajectories• 2 ps• 0.5 fs step

Formamide in Ar matrix

• Eckert-Maksic, Vazdar, Ruckenbauer, Barbatti, Muller, Lischka, PCCP 12, 12719 (2010)

O

NH2

H2

O

NH

0.5 ps O

CH

NH2…. (47%)

0.5 psO

NH2

(22%)

O

NH2

*

(16%)

2 ps

O

CNH3 ..... (15%)

1 ps

+> 2ps

O

CNH3 .....> 2ps

> 2ps?

?

?

Formamide in Ar matrix

• Eckert-Maksic, Vazdar, Ruckenbauer, Barbatti, Muller, Lischka, PCCP 12, 12719 (2010)

Me-formamide in the gas phase

• Crespo-Otero, Mardyukov, Sanchez-Garcia, Barbatti, Sander, ChemPhysChem 14, 827 (2013)

Case 5: Prebiotic reactions

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Prebiotic route for nucleotides

• Powner, Sutherland, Szostak, JACS 132, 16677 (2010)

• Ferris, Orgel, JACS 88, 1074 (1966)

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Computational chemistry in action

Dynamics and Chemical Kinetics revealed the

only possible route

QM/MM: hot 4HCN in water

RRKM

24

Photochem in prebiotic synthesis

• Boulanger, Anoop, Nachtigallova, Thiel, MB, ACIE 52, 8000 (2013)

4HCN

purinenucleotides

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Next lecture:

• Surface hopping with single reference methods

Contactbarbatti@kofo.mpg.de

www.youtube.com/user/mbarbatti