ramanova spektroskopija - unios.hrkolegij.fizika.unios.hr/afs/files/2014/10/9_raman.pdf ·...
TRANSCRIPT
![Page 1: Ramanova spektroskopija - unios.hrkolegij.fizika.unios.hr/afs/files/2014/10/9_Raman.pdf · Predavanje 9 Atomska fizika i spektroskopija . ... Ramanova spektroskopija ... determine](https://reader036.vdocument.in/reader036/viewer/2022081507/5af84cc37f8b9abd588b678a/html5/thumbnails/1.jpg)
Ramanova spektroskopija
Igor Lukacevic, Dept. Of Physics, UJJS
Predavanje 9 Atomska fizika i spektroskopija
![Page 2: Ramanova spektroskopija - unios.hrkolegij.fizika.unios.hr/afs/files/2014/10/9_Raman.pdf · Predavanje 9 Atomska fizika i spektroskopija . ... Ramanova spektroskopija ... determine](https://reader036.vdocument.in/reader036/viewer/2022081507/5af84cc37f8b9abd588b678a/html5/thumbnails/2.jpg)
Sadrzaj
Uvod
Princip rada
Osobine Ramanove spektroskopije
Instrumentacija
Primjene
![Page 3: Ramanova spektroskopija - unios.hrkolegij.fizika.unios.hr/afs/files/2014/10/9_Raman.pdf · Predavanje 9 Atomska fizika i spektroskopija . ... Ramanova spektroskopija ... determine](https://reader036.vdocument.in/reader036/viewer/2022081507/5af84cc37f8b9abd588b678a/html5/thumbnails/3.jpg)
Ramanova spektroskopija – uvod
C. V. Raman (1888 – 1970)
• Nobelova nagrada 1930.
• Journey into Light: Life
and Science of C. V.
Raman, G.
Venkataraman, 1988.
![Page 4: Ramanova spektroskopija - unios.hrkolegij.fizika.unios.hr/afs/files/2014/10/9_Raman.pdf · Predavanje 9 Atomska fizika i spektroskopija . ... Ramanova spektroskopija ... determine](https://reader036.vdocument.in/reader036/viewer/2022081507/5af84cc37f8b9abd588b678a/html5/thumbnails/4.jpg)
Ramanova spektroskopija – uvod
Ramanovo rasprsenje ili Ramanov efekt
Neelasticno rasprsenje fotona.
![Page 5: Ramanova spektroskopija - unios.hrkolegij.fizika.unios.hr/afs/files/2014/10/9_Raman.pdf · Predavanje 9 Atomska fizika i spektroskopija . ... Ramanova spektroskopija ... determine](https://reader036.vdocument.in/reader036/viewer/2022081507/5af84cc37f8b9abd588b678a/html5/thumbnails/5.jpg)
Ramanova spektroskopija – uvod
Osnovne osobine
Dotice se rovibracijske strukture tvari
Uzorak u plinovitom, tekucem ili krutom stanju
Izvor zracenja – laser
Ne mijesati s fluorescencijom
![Page 6: Ramanova spektroskopija - unios.hrkolegij.fizika.unios.hr/afs/files/2014/10/9_Raman.pdf · Predavanje 9 Atomska fizika i spektroskopija . ... Ramanova spektroskopija ... determine](https://reader036.vdocument.in/reader036/viewer/2022081507/5af84cc37f8b9abd588b678a/html5/thumbnails/6.jpg)
Ramanova spektroskopija – princip
![Page 7: Ramanova spektroskopija - unios.hrkolegij.fizika.unios.hr/afs/files/2014/10/9_Raman.pdf · Predavanje 9 Atomska fizika i spektroskopija . ... Ramanova spektroskopija ... determine](https://reader036.vdocument.in/reader036/viewer/2022081507/5af84cc37f8b9abd588b678a/html5/thumbnails/7.jpg)
Ramanova spektroskopija – princip
Ram
an
ov p
om
ak
∆𝜔
𝑐𝑚−1
=1 λ0−
1 λ1
Stokesov pomak:
𝐸𝑓 > 𝐸𝑖, 𝜔𝑜𝑢𝑡 < 𝜔𝑖𝑛
Rayleighevo rasprsenje: 𝐸𝑓 = 𝐸𝑖,
𝜔𝑜𝑢𝑡 = 𝜔𝑖𝑛
Anit-Stokesov pomak: 𝐸𝑓 < 𝐸𝑖, 𝜔𝑜𝑢𝑡 > 𝜔𝑖𝑛
![Page 8: Ramanova spektroskopija - unios.hrkolegij.fizika.unios.hr/afs/files/2014/10/9_Raman.pdf · Predavanje 9 Atomska fizika i spektroskopija . ... Ramanova spektroskopija ... determine](https://reader036.vdocument.in/reader036/viewer/2022081507/5af84cc37f8b9abd588b678a/html5/thumbnails/8.jpg)
Spectrum of CCl4, using an Ar+
laser at 488 nm
Ramanova spektroskopija – princip
![Page 9: Ramanova spektroskopija - unios.hrkolegij.fizika.unios.hr/afs/files/2014/10/9_Raman.pdf · Predavanje 9 Atomska fizika i spektroskopija . ... Ramanova spektroskopija ... determine](https://reader036.vdocument.in/reader036/viewer/2022081507/5af84cc37f8b9abd588b678a/html5/thumbnails/9.jpg)
The oscillating electric field of the excitation light.
The induced dipole moment from this oscillating field.
The molecular polarizability changes with bond length.
The bond length oscillates at vibrational frequency.
Hence the polarizability oscillates at same frequency.
Substitute.
Remember trig identity.
Induced dipole has Rayleigh,
Stokes, and anti-Stokes
components.
E E0 cosext
induced E E0 cos ex t
0 r req d
dr
r req rmax cosvibt
0 d
dr
rmax cosvibt
induced 0 d
dr
rmax cos vibt
E0 cosex t 0E0 cos ex t
E0rmaxd
dr
cos ex t cosvibt
cosx cosy 1
2cos x y cos x y
induced 0E0 cosex t
E0rmax
2
d
dr
cos ex vib t cos ex vib t
Ramanova spektroskopija – princip
![Page 10: Ramanova spektroskopija - unios.hrkolegij.fizika.unios.hr/afs/files/2014/10/9_Raman.pdf · Predavanje 9 Atomska fizika i spektroskopija . ... Ramanova spektroskopija ... determine](https://reader036.vdocument.in/reader036/viewer/2022081507/5af84cc37f8b9abd588b678a/html5/thumbnails/10.jpg)
Ramanova spektroskopija – princip
Molekularna polarizabilnost
![Page 11: Ramanova spektroskopija - unios.hrkolegij.fizika.unios.hr/afs/files/2014/10/9_Raman.pdf · Predavanje 9 Atomska fizika i spektroskopija . ... Ramanova spektroskopija ... determine](https://reader036.vdocument.in/reader036/viewer/2022081507/5af84cc37f8b9abd588b678a/html5/thumbnails/11.jpg)
Ramanova spektroskopija – princip
Molekularna polarizabilnost
𝑟~1
𝜖
![Page 12: Ramanova spektroskopija - unios.hrkolegij.fizika.unios.hr/afs/files/2014/10/9_Raman.pdf · Predavanje 9 Atomska fizika i spektroskopija . ... Ramanova spektroskopija ... determine](https://reader036.vdocument.in/reader036/viewer/2022081507/5af84cc37f8b9abd588b678a/html5/thumbnails/12.jpg)
Spektar PETN
eksploziva (D.N.
Batchelder, Univ. of
Leeds)
Ramanova spektroskopija – osobine
![Page 13: Ramanova spektroskopija - unios.hrkolegij.fizika.unios.hr/afs/files/2014/10/9_Raman.pdf · Predavanje 9 Atomska fizika i spektroskopija . ... Ramanova spektroskopija ... determine](https://reader036.vdocument.in/reader036/viewer/2022081507/5af84cc37f8b9abd588b678a/html5/thumbnails/13.jpg)
Nedestruktivna / neinvazivna
metoda
Ne ovisi o temperaturi/tl
aku
ν ≥ 100 𝑐𝑚−1 Jednostavna mikroskopija
Jednostavna ili nikakva priprema
uzorka (voda odlicno
otapalo za Raman i ne rasprsuje se na plastici ili
staklu)
Prednosti Ramanove spektroskopije
Ramanova spektroskopija – osobine
![Page 14: Ramanova spektroskopija - unios.hrkolegij.fizika.unios.hr/afs/files/2014/10/9_Raman.pdf · Predavanje 9 Atomska fizika i spektroskopija . ... Ramanova spektroskopija ... determine](https://reader036.vdocument.in/reader036/viewer/2022081507/5af84cc37f8b9abd588b678a/html5/thumbnails/14.jpg)
Ramanova spektroskopija – osobine
![Page 15: Ramanova spektroskopija - unios.hrkolegij.fizika.unios.hr/afs/files/2014/10/9_Raman.pdf · Predavanje 9 Atomska fizika i spektroskopija . ... Ramanova spektroskopija ... determine](https://reader036.vdocument.in/reader036/viewer/2022081507/5af84cc37f8b9abd588b678a/html5/thumbnails/15.jpg)
Ramanova spektroskopija – osobine
Spektar antracena
A: Ar+ laser (514.5 nm)
B: Nd:YAG laser (1064 nm)
𝐼~1
λ4 →
zelimo krace λ
Fluorescencija → zelimo duze λ
![Page 16: Ramanova spektroskopija - unios.hrkolegij.fizika.unios.hr/afs/files/2014/10/9_Raman.pdf · Predavanje 9 Atomska fizika i spektroskopija . ... Ramanova spektroskopija ... determine](https://reader036.vdocument.in/reader036/viewer/2022081507/5af84cc37f8b9abd588b678a/html5/thumbnails/16.jpg)
• Rayleigh = 105 – 106 SS ili ASS
• ψ𝑣𝑖𝑟𝑡 ≈ ψ𝑟𝑒𝑎𝑙 → 𝑃𝑔𝑠→𝑒𝑥𝑐 ≈ 1
• 𝐼𝑟𝑒𝑠 = 102 − 106 𝐼𝑟𝑎𝑚𝑎𝑛
• c ≥ 10-8 M
• kromofor
Ramanova spektroskopija – osobine
Rezonantni Ramanov ucinak
![Page 17: Ramanova spektroskopija - unios.hrkolegij.fizika.unios.hr/afs/files/2014/10/9_Raman.pdf · Predavanje 9 Atomska fizika i spektroskopija . ... Ramanova spektroskopija ... determine](https://reader036.vdocument.in/reader036/viewer/2022081507/5af84cc37f8b9abd588b678a/html5/thumbnails/17.jpg)
Ramanova spektroskopija – osobine
• Surface-enhanced Raman spectroscopy
• Resonance Raman spectroscopy
• Surface-enhanced resonance Raman spectroscopy (SERRS)
• Angle-resolved Raman spectroscopy
• Hyper Raman
• Spontaneous Raman spectroscopy (SRS)
• Optical tweezers Raman spectroscopy (OTRS)
• Stimulated Raman spectroscopy
• Spatially offset Raman spectroscopy (SORS)
• Coherent anti-Stokes Raman spectroscopy (CARS)
• Raman optical activity
• Transmission Raman
• Inverse Raman spectroscopy.
• Tip-enhanced Raman spectroscopy (TERS)
• Surface plasmon polaritons enhanced Raman scattering (SPPERS)
![Page 18: Ramanova spektroskopija - unios.hrkolegij.fizika.unios.hr/afs/files/2014/10/9_Raman.pdf · Predavanje 9 Atomska fizika i spektroskopija . ... Ramanova spektroskopija ... determine](https://reader036.vdocument.in/reader036/viewer/2022081507/5af84cc37f8b9abd588b678a/html5/thumbnails/18.jpg)
Instrumentacija
• Slab I → treba jak intenzitet
• Monokromatski izvor → jednostavniji spektar
• Monokromatski izvor → niska snaga
Lampe
•Ar+ Ion: 488.0 and 514.5 nm
•Kr+ Ion: 530.9 and 647.1 nm
•He:Ne: 632.8 nm
•Diode Lasers: 782 and 830 nm
•Nd: YAG: 1064 (532 when doubled) nm
Laseri
500 mW Ar ion laser – eBay $1000
![Page 19: Ramanova spektroskopija - unios.hrkolegij.fizika.unios.hr/afs/files/2014/10/9_Raman.pdf · Predavanje 9 Atomska fizika i spektroskopija . ... Ramanova spektroskopija ... determine](https://reader036.vdocument.in/reader036/viewer/2022081507/5af84cc37f8b9abd588b678a/html5/thumbnails/19.jpg)
Tipicne snage izvora
Ion lasers, 40 W cw
He:Ne, 10 W cw
YAG (Yttrium aluminium garnet – Y3Al5O12), 1 J/10 ns pulse (100 MW average pulse)
Poboljsani detektori – potrebna manja snaga
Diode laser, 25 mW
Ar+, 5 mW
Instrumentacija
SSD, SDD, SPD, PIN, CCD
![Page 20: Ramanova spektroskopija - unios.hrkolegij.fizika.unios.hr/afs/files/2014/10/9_Raman.pdf · Predavanje 9 Atomska fizika i spektroskopija . ... Ramanova spektroskopija ... determine](https://reader036.vdocument.in/reader036/viewer/2022081507/5af84cc37f8b9abd588b678a/html5/thumbnails/20.jpg)
• laser (NIR ili Vis) +
interferometar
• array detektori
Instrumentacija
FT Raman
![Page 21: Ramanova spektroskopija - unios.hrkolegij.fizika.unios.hr/afs/files/2014/10/9_Raman.pdf · Predavanje 9 Atomska fizika i spektroskopija . ... Ramanova spektroskopija ... determine](https://reader036.vdocument.in/reader036/viewer/2022081507/5af84cc37f8b9abd588b678a/html5/thumbnails/21.jpg)
Multichannel Raman Spectroscopy
Instrument of Hans Hallen in Phyiscs Dept. at North Carolina State.
![Page 22: Ramanova spektroskopija - unios.hrkolegij.fizika.unios.hr/afs/files/2014/10/9_Raman.pdf · Predavanje 9 Atomska fizika i spektroskopija . ... Ramanova spektroskopija ... determine](https://reader036.vdocument.in/reader036/viewer/2022081507/5af84cc37f8b9abd588b678a/html5/thumbnails/22.jpg)
KTiOPO4 + Rb
NSOM Raman Imaging
A near-field scanning microscope was used and the Raman signal was
used to key the substrate response.
![Page 23: Ramanova spektroskopija - unios.hrkolegij.fizika.unios.hr/afs/files/2014/10/9_Raman.pdf · Predavanje 9 Atomska fizika i spektroskopija . ... Ramanova spektroskopija ... determine](https://reader036.vdocument.in/reader036/viewer/2022081507/5af84cc37f8b9abd588b678a/html5/thumbnails/23.jpg)
Chemical Mapping
• Focus laser to small spot.
• Tune spectrometer to particular Raman transition peak.
• Raster scan the sample under the laser beam, record intensity changes. Resultant map correlates with
substance.
• Acquire an entire spectrum at every point, then choose the feature
with which to key the image.
Motorized stage from
Renishaw for chemical
mapping.
This is a drug tablet.
The yellow
corresponds to the
active ingredient.
Particles are in the
10’s of µm range.
![Page 24: Ramanova spektroskopija - unios.hrkolegij.fizika.unios.hr/afs/files/2014/10/9_Raman.pdf · Predavanje 9 Atomska fizika i spektroskopija . ... Ramanova spektroskopija ... determine](https://reader036.vdocument.in/reader036/viewer/2022081507/5af84cc37f8b9abd588b678a/html5/thumbnails/24.jpg)
Chemical Imaging
• Now defocus the laser (not a small spot, but rather “baths” the sample in laser radiation).
• Pass the emitted radiation through a narrow bandpass filter, adjusted to a particular
wavelength, chosen to be a certain Raman band.
• Focus this light on the CCD camera. Bright regions correspond to locations of substance giving
rise to Raman signal.
Mixture of cocaine and sugar. Bright spots are cocaine.
![Page 25: Ramanova spektroskopija - unios.hrkolegij.fizika.unios.hr/afs/files/2014/10/9_Raman.pdf · Predavanje 9 Atomska fizika i spektroskopija . ... Ramanova spektroskopija ... determine](https://reader036.vdocument.in/reader036/viewer/2022081507/5af84cc37f8b9abd588b678a/html5/thumbnails/25.jpg)
Primjena u restauraciji
• Ovo je freska iz 12. st. iz crkve u Italiji, koju je
trebalo restaurirati
• Koje boje upotrijebiti?
• Raman analiza pomoću Ramanove spektroskopije
identificira boje i pigmente koji su prisutni u originalu,
dozvoljavajući ispravan izbor materijala za čišćenje i
ponovno bojanje nakon toga, kako bi se vratilo
originalno stanje
![Page 26: Ramanova spektroskopija - unios.hrkolegij.fizika.unios.hr/afs/files/2014/10/9_Raman.pdf · Predavanje 9 Atomska fizika i spektroskopija . ... Ramanova spektroskopija ... determine](https://reader036.vdocument.in/reader036/viewer/2022081507/5af84cc37f8b9abd588b678a/html5/thumbnails/26.jpg)
Applications - Paint Chips
Forensic analysis of paint chips in vehicle accidents. Often
multiple layers. Can analyze with IR by stripping successive
layers. Image edge with microRaman.
• Layers 1 and 3 turned out to be rutile phase TiO2 - a white
paint.
• Layer 2 was a goethite, a red pigment and corrosion inhibitor.
• Layer 4 was molybdate orange, a common red paint in the 70’s
in North America and still used in the U.K. today.
• Layer 5 was a silicate based paint. Data arising from a case
investigated by LAPD.
![Page 27: Ramanova spektroskopija - unios.hrkolegij.fizika.unios.hr/afs/files/2014/10/9_Raman.pdf · Predavanje 9 Atomska fizika i spektroskopija . ... Ramanova spektroskopija ... determine](https://reader036.vdocument.in/reader036/viewer/2022081507/5af84cc37f8b9abd588b678a/html5/thumbnails/27.jpg)
Applications - Gem Forgery
GE POL (1999) →
brown type IIa diamonds = naturally clear diamonds
![Page 28: Ramanova spektroskopija - unios.hrkolegij.fizika.unios.hr/afs/files/2014/10/9_Raman.pdf · Predavanje 9 Atomska fizika i spektroskopija . ... Ramanova spektroskopija ... determine](https://reader036.vdocument.in/reader036/viewer/2022081507/5af84cc37f8b9abd588b678a/html5/thumbnails/28.jpg)
Applications - Gem Forgery
GE POL (1999) →
brown type IIa diamonds = naturally clear diamonds
Naturally clear diamond Originally brown diamond
![Page 29: Ramanova spektroskopija - unios.hrkolegij.fizika.unios.hr/afs/files/2014/10/9_Raman.pdf · Predavanje 9 Atomska fizika i spektroskopija . ... Ramanova spektroskopija ... determine](https://reader036.vdocument.in/reader036/viewer/2022081507/5af84cc37f8b9abd588b678a/html5/thumbnails/29.jpg)
Applications - Bullet Proof Glass
Identify poly(carbonate) from poly(methylmethacrylate).
Both used for shatter-proof glass
![Page 30: Ramanova spektroskopija - unios.hrkolegij.fizika.unios.hr/afs/files/2014/10/9_Raman.pdf · Predavanje 9 Atomska fizika i spektroskopija . ... Ramanova spektroskopija ... determine](https://reader036.vdocument.in/reader036/viewer/2022081507/5af84cc37f8b9abd588b678a/html5/thumbnails/30.jpg)
Applications - Sunscreen Formulations
Here are the spectra of 5 common
sunscreen ingredients. Raman is able to
determine from a spectrum on the arm
the nature of the sunscreen being used.
A: ODPABA (octyl N,N-dimethyl-p-
aminobenzoic acid)
B: OMC (octyl p-methoxycinnamate)
C: BZ3 (oxybenzone)
D: OCS (octyl salicylate)
E: DBM (dibenzoylmethane)
G. R. Luppnow et al.,
J. Raman. Spec. 34,
743 (2003).
![Page 31: Ramanova spektroskopija - unios.hrkolegij.fizika.unios.hr/afs/files/2014/10/9_Raman.pdf · Predavanje 9 Atomska fizika i spektroskopija . ... Ramanova spektroskopija ... determine](https://reader036.vdocument.in/reader036/viewer/2022081507/5af84cc37f8b9abd588b678a/html5/thumbnails/31.jpg)
Literatura
1. http://cartwright.chem.ox.ac.uk/tlab/605/html/introduction01.htm
2. http://www.spectroscopynow.com/raman?tzcheck=1
3. http://www.wurm.info/
4. http://rruff.info/
5. http://www.horiba.com/de/scientific/products/raman-spectroscopy/
6. http://nsdl.niscair.res.in/bitstream/123456789/801/1/
7. http://www.azom.com/article.aspx?ArticleID=10089
8. http://www.gia.edu/