scholarly journals Coherent Motion of Low Frequency Vibrations in Ultrafast Excited State Proton Transfer

1999 ◽  
Vol 19 (1-4) ◽  
pp. 101-103 ◽  
Author(s):  
M. Pfeiffer ◽  
C. Chudoba ◽  
A. Lau ◽  
K. Lenz ◽  
T. Elsaesser
Keyword(s):  
Proton Transfer ◽  
Low Frequency ◽  
Coherent Motion ◽  
Vibrational Modes ◽  
Nuclear Movement ◽  
Normal Coordinate ◽  
Pump Probe ◽  
Transfer Path ◽  
Resonance Raman Spectra ◽  
First Time

Photoexcitation of internal proton transfer in the tinuvin molecule causes the excitation of some low frequency vibrational modes which oscillate with high amplitudes in a coherent manner over 700 fs. Such effect is observed for the first time applying two color pump/probe measurement with 25 fs pulses. Based on resonance Raman spectra a normal coordinate analysis of the modes is performed. It is shown that the nuclear movement given by the normal vibration of one of the modes serves to open up a barrierfree proton transfer path.

scholarly journals Time-Resolved Terahertz Spectroscopy of Condensed Phase Reactions

1999 ◽  
Vol 19 (1-4) ◽  
pp. 145-148
Author(s):  
Richard McElroy ◽  
Klaas Wynne
Keyword(s):  
Terahertz Spectroscopy ◽  
Low Frequency ◽  
Electronic States ◽  
Carrier Dynamics ◽  
Solvation Dynamics ◽  
Vibrational Modes ◽  
Time Resolved ◽  
Condensed Phase Reactions ◽  
Probe Spectroscopy ◽  
First Time

Ultrafast time-resolved visible-pump, far-IR (THz) probe spectroscopy has been developed in our lab and has been applied to study carrier dynamics in photoexcited GaAs and dipole solvation dynamics in betaine and p-nitroaniline. This type of spectroscopy enables us to study for the first time the nonequilibrium interaction between excited electronic states and low frequency vibrational modes.

Ultraviolet Resonance Raman Study of Nylon-6

1995 ◽  
Vol 49 (6) ◽  
pp. 773-779 ◽  
Author(s):  
Gen Katagiri ◽  
James D. Leonard ◽  
Terry L. Gustafson
Keyword(s):  
Laser System ◽  
Resonance Raman ◽  
Nylon 6 ◽  
Vibrational Modes ◽  
Raman Study ◽  
Resonance Raman Spectra ◽  
Ultraviolet Resonance Raman ◽  
Selective Enhancement ◽  
First Time ◽  
Uv Excitation

Ultraviolet resonance Raman spectra of nylon-6 have been investigated with the use of a quasi-continuous UV excitation source based on cw mode-locked Nd:YAG and Nd:YLF lasers. The selective enhancement of the amide vibrational modes is discussed in relation to the reported results for simple amide compounds and polypeptides in aqueous solution. The ultraviolet excitation can extract the amide III mode at 1280 cm−1 for the first time, from significantly overlapped CH2 vibrational modes. The UV-enhanced mode is observed at 1380 cm−1 and is attributed to the controversial amide S mode. We also demonstrate the utility of the present quasi-continuous laser system as an excellent UV source for ultraviolet resonance Raman studies of solid materials.

Complex formation and kinematic coupling: C2H4.PtCl3

1988 ◽  
Vol 53 (10) ◽  
pp. 2377-2384 ◽  
Author(s):  
Roman Řeřicha ◽  
Björg N. Cyvin ◽  
Jon Brunvoll ◽  
Sven J. Cyvin
Keyword(s):  
Complex Formation ◽  
Crystallographic Data ◽  
System Modelling ◽  
Vibrational Modes ◽  
Normal Coordinate ◽  
Kinematic Coupling ◽  
Fundamental Frequencies

Normal coordinate analyses including calculations of PED's were performed for C2H4.PtCl3 system modelling Zeise's anion, [(C2H4)PtCl3]-. The wedgewise distorsion of the C2H4 ligand known from the crystallographic data for Zeise's salt, was taken into account. Under these circumstances it was found that the kinematic couplings between the internal ligand and complex framework vibrational modes are rather small. The reliability of some existing assignments of the fundamental frequencies of Zeise's anion is discussed.

scholarly journals Low frequency vibrational modes of oxygenated myoglobin, hemoglobins, and modified derivatives.

1994 ◽  
Vol 269 (49) ◽  
pp. 31047-31050
Author(s):  
S Jeyarajah ◽  
L M Proniewicz ◽  
H Bronder ◽  
J R Kincaid
Keyword(s):  
Low Frequency ◽  
Vibrational Modes

scholarly journals Moduli and modes in the Mikado model

Soft Matter ◽  
2021 ◽  
Author(s):  
Brian Tighe ◽  
Karsten Baumgarten
Keyword(s):  
Shear Modulus ◽  
Mechanical Model ◽  
Low Frequency ◽  
Vibrational Modes ◽  
Prior Work ◽  
Fiber Networks ◽  
Elastic Shear Modulus ◽  
Flexible Fiber ◽  
Elastic Shear

We determine how low frequency vibrational modes control the elastic shear modulus of Mikado networks, a minimal mechanical model for semi-flexible fiber networks. From prior work it is known that...

Darstellung, Schwingungsspektren und Normalkoordinatenanalyse von Chloro-Bromo-Rhodaten(III) / Preparation, Vibration Spectra and Normal Coordinate Analysis of Chloro-Bromo-Rhodates(III)

1989 ◽  
Vol 44 (10) ◽  
pp. 1221-1227 ◽  
Author(s):  
W. Preetz ◽  
W. Kuhr
Keyword(s):  
Exchange Chromatography ◽  
Trans Isomers ◽  
Normal Coordinate ◽  
Valence Force ◽  
Trans Influence ◽  
Diethylaminoethyl Cellulose ◽  
Point Groups ◽  
First Time ◽  
Ir And Raman ◽  
Good Agreement

The mixed chloro-bromo-rhodates(III) [RhClnBr6-n]3-, n = 1-5, have been separated for the first time by ion exchange chromatography on diethylaminoethyl-cellulose. Due to the stronger trans-effect of Br, as compared with Cl, on treatment of [RhBr6]3- with conc. HCl nearly pure cis/fac-isomers for n = 2, 3, 4 are formed. The reaction of [RhCl6]3- with conc. HBr yields mixtures of the cis/trans-isomers for n = 2, 4, which cannot be separated, but mer-[RhCl3Br3]3 is formed stereospecifically. The IR and Raman spectra of all isolated mixed ligand complexes are completely assigned according to point groups Oh, D3d, C4v, C3v and C2v, supported by normal coordinate analyses based on a general valence force field. The good agreement of calculated and observed frequencies confirms the assignments. Due to the stronger trans-influence of Br as compared to Cl, in all asymmetric Cl—Rh—Br axes the Rh—Br bonds are strengthened and the Rh—Cl bonds are weakened, indicated by valence force constants for Rh—Br approximately 14% higher, for Rh—Cl 10% lower, as compared with the values calculated for symmetric Br—Rh—Br and Cl—Rh—Cl axes, respectively.

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