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.

Vibrational Spectra of Phenylphosphonic and Phenylthiophosphonic Acid and their Complete Assignment

2010 ◽  
Vol 65 (3) ◽  
pp. 357-s374 ◽  
Author(s):  
Wolfgang Förner ◽  
Hassan M. Badawi
Keyword(s):  
Conformational Equilibrium ◽  
Dihedral Angles ◽  
Torsional Angle ◽  
Vibrational Modes ◽  
Infrared And Raman Spectra ◽  
Normal Coordinate ◽  
Energy Distributions ◽  
Phenylphosphonic Acid ◽  
Low Intensity ◽  
Complete Assignment

The structures and conformational stabilities of phenylphosphonic acid and phenylthiophosphonic acid were investigated using calculations mostly at DFT/6-311G** and ab initio MP2/6-311G** level. From the calculations the molecules were predicted to exist in a conformational equilibrium consisting of two conformers which as enantiomers have the same energy, but rather unexpected dihedral angles XPCC (X being O or S) which are not equal to zero. The antisymmetric potential function for the internal rotation was determined for each one of the molecules. In these functions the conformers with zero dihedral angles appear to be stable minima (also optimization converges to this), but the vibrational frequency for the torsion turned out to be imaginary, indicating that they are maxima with respect to this symmetry coordinate. Only optimization without any restrictions and starting from a non-zero torsional angle converged to a real minimum with such a geometry (“non-planar”). For that minimum structure infrared and Raman spectra were calculated, and those for phenylphosphonic acid were compared to experimental data, showing satisfactory agreement. This gives confidence to present the spectra of phenylthiophosphonic acid as a prediction. The rather low intensity of the OH bands in the experimental infrared spectrum (as compared to normal organic acids) indicates rather weak hydrogen bonding. Normal coordinate calculations were carried out, and potential energy distributions were calculated for the molecules in the non (near)-planar conformations providing a complete assignment of the vibrational modes to atomic motions in the molecules. From the rather low rotational barriers we conclude, in agreement with results from the literature (for other P=O compounds) based on localized orbitals that conjugation effects are absent - or at least negligible - as compared to electrostatic and steric ones in determining the structures of the stable conformers in the phenyl derivatives. The P=O (and also the P=S) bond is highly polarized according to our analysis of Mulliken populations. The polarization turned out to be smaller in the thiophosphonic acid due to the smaller electronegativity of sulfur as compared to oxygen.

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.

Electronic Structure, Nonlinear Optical Properties, and Vibrational Analysis of Ethyl benzoate by Density Functional Theory

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Tanveer Hasan ◽  
P. K. Singh
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Vibrational Analysis ◽  
Ethyl Benzoate ◽  
Computational Method ◽  
Basis Set ◽  
Vibrational Modes ◽  
Normal Coordinate ◽  
Functional Theory ◽  
Vibrational Bands

This work deals with the vibrational spectroscopy of Ethyl benzoate (C9H10O2). The fundamental vibrational frequencies and intensity of vibrational bands were evaluated using density functional theory (DFT) using standard HF/6-31G(d,p) and B3LYP/6-31G(d,p) methods and basis set combinations. The vibrational spectra were interpreted, with the aid of normal coordinate analysis based on a scaled quantum mechanical force field. The infrared and Raman spectra were also predicted from the calculated intensities. Comparison of simulated spectra with the experimental spectra provides important information about the ability of the computational method to describe the vibrational modes.

Vibrational Spectra of Bis-(Monothioacetylacetonato) Ni(II)

1969 ◽  
Vol 23 (3) ◽  
pp. 224-229 ◽  
Author(s):  
Umesh Agarwala ◽  
P. Bhaskara Rao
Keyword(s):  
Infrared Spectra ◽  
Vibrational Spectra ◽  
Normal Coordinate Analysis ◽  
The Other ◽  
Methyl Groups ◽  
Vibrational Modes ◽  
Normal Coordinate ◽  
Conjugated Systems

The infrared spectra of substituted acetylacetonates have been discussed in the light of normal coordinate analysis of bis-(monothioacetylacetonato) Ni(II) assuming methyl groups as point masses. The Urey-Bradley potential constants evaluated are found to be quite close to those of analogous systems studied earlier. The calculations show that each of the fundamental bands results from vibrational modes involving appreciable contributions from a number of bonds. The single major contribution from the stretching of C = S has been found in the 723 cm−1 band. This is in agreement with the other conjugated systems, like thioamides, studied earlier.

Darstellung und Schwingungsspektren von cis- und trans-[OsXY(acac)2], X ≠ Y = Cl, Br, I sowie Normalkoordinatenanalyse von trans-[OsClBr(acac)2]/Synthesis and Vibrational Spectra of cis- and trans-[OsXY(acac)2], X ≠ Y = Cl, Br, I, and Normal Coordinate Analysis of trans-[OsClBr(acac)2]

1998 ◽  
Vol 53 (2) ◽  
pp. 227-231
Author(s):  
K. Dallmann ◽  
W. Preetz
Keyword(s):  
Normal Coordinate Analysis ◽  
Force Constants ◽  
Vibrational Modes ◽  
Normal Coordinate ◽  
Valence Force ◽  
Valence Force Field ◽  
Stretching Vibrations ◽  
Cis And Trans ◽  
Ir And Raman ◽  
Good Agreement

Abstract In the reaction of K2[OsX3 Y3] with boiling water/acetylacetone (1:1) the six mixed com­plexes cis-and trans-[OsX2 (acac)2] (X ≠ Y = Cl, Br, I) are formed, which have been purified by column chromatography with toluene on silica gel. The IR and Raman spectra (10K) show the intraligand vibrations of the acac groups with nearly constant frequencies and the stretching vibrations of OsO in the range 460-696, of OsCl at 315-345, of OsBr at 210-225, and of Osl at 160-175 cm-1 . A normal coordinate analysis based on a modified valence force field was performed for trans-[OsClBr(acac)2] and the vibrational modes have been assigned. With a set of 32 force constants, taking into account the intraligand vibrations, a good agreement between observed and calculated frequencies has been achieved. The valence force constants are fd (OsCl•) = 1.75, fd(OsBr′) = 1.63 and fd (OsO) = 3.27 mdyn/Å.

scholarly journals The Vibrational Spectra of Silane and Germane Derivatives. Part IV. The Infrared and Raman Spectra of the Iodo(methyl)germanes

1971 ◽  
Vol 49 (18) ◽  
pp. 2931-2936 ◽  
Author(s):  
J. W. Anderson ◽  
G. K. Barker ◽  
J. E. Drake And ◽  
R. T. Hemmings
Keyword(s):  
Force Field ◽  
Raman Spectra ◽  
Vibrational Spectra ◽  
A Priori ◽  
Normal Coordinate Analysis ◽  
Infrared And Raman Spectra ◽  
Normal Coordinate ◽  
Valence Force ◽  
Valence Force Field ◽  
Fundamental Frequencies

The infrared and Raman spectra of the series of iodo(methyl)germanes, CH3GeI3, (CH3)2GeI2, and (CH3)3GeI have been recorded. A normal coordinate analysis based on a modified valence force field confirms the a priori assignments for all of the fundamental frequencies except the torsional modes.

scholarly journals Stability, diffusion, and complex formation of beryllium in wurtzite GaN

2000 ◽  
Vol 639 ◽  
Author(s):  
Sukit Limpijumnong ◽  
Chris G. Van de Walle ◽  
Jörg Neugebauer
Keyword(s):  
Complex Formation ◽  
First Principles ◽  
Formation Energy ◽  
Potential Problem ◽  
Vibrational Modes ◽  
First Principles Calculations ◽  
Experimental Identification ◽  
Donor Character ◽  
Formation Of Complexes

ABSTRACTWe have studied the properties of Be dopants in GaN using first principles calculations. Substitutional Be on a Ga site acts as an acceptor, but interstitial Be poses a potential problem because of its low formation energy and donor character. We study the diffusion of interstitial Be and find it to be highly anisotropic. We also study the formation of complexes between substitutional and interstitial Be, and between substitutional Be and hydrogen. We have calculated the Be-H vibrational modes to aid in experimental identification of such complexes.

FTIR, FTR Spectral Analysis and DFT Calculations of 1, 8-Dimethyl Naphthalene

2012 ◽  
Vol 584 ◽  
pp. 371-375
Author(s):  
V. Pouchaname ◽  
R. Madivanane ◽  
A. Tinabaye
Keyword(s):  
Spectral Analysis ◽  
Dft Calculations ◽  
Raman Spectra ◽  
Solid Phase ◽  
Computational Method ◽  
Basis Sets ◽  
Vibrational Modes ◽  
Normal Coordinate ◽  
Good Agreement ◽  
Ft Raman

ABSTRACT. Solid phase FTIR and FT-Raman spectra of 1, 8-dimethylnaphthalene have been recorded in the region 3700-50 cm-1. The spectra were interpreted with aid of normal coordinate analysis based on DFT using standard B3LYP/6-31G basis sets. After scaling there is good agreement between observed and calculated frequencies. Comparison of the simulated spectra with the experimental spectra provides important information about the ability of the computational method to describe the vibrational modes.

Vibrational spectra of thiocarbonyl chlorofluoride and a normal coordinate analysis of thiocarbonyl chlorofluoride and thiocarbonyl difluoride

1969 ◽  
Vol 47 (6) ◽  
pp. 1011-1017 ◽  
Author(s):  
D. C. Moule ◽  
C. R. Subramaniam
Keyword(s):  
Vibrational Spectra ◽  
Valence Bond ◽  
Marked Change ◽  
Ultra Violet ◽  
Infrared And Raman Spectra ◽  
Normal Coordinate ◽  
Fundamental Frequencies ◽  
Ionic Valence ◽  
Partial Analysis ◽  
Out Of Plane

The previously unreported infrared and Raman spectra of thiocarbonyl chlorofluoride have been obtained and analyzed. An assignment has been made for the in-plane fundamental frequencies. The frequency of the out-of-plane fundamental has been obtained from a partial analysis of the near ultra-violet (π*n) system. Normal coordinate analyses for thiocarbonyl fluoride and thiocarbonyl chlorofluoride have been carried out using the Urey–Bradley potential field. The value of the CS stretching force constant is found to show a marked change with the halogen substitution in contrast to the CO stretching constant in the carbonyl halides. This is attributed to the presence of ionic valence bond structures in the thiocarbonyl halides which are not significant in the carbonyl halides.

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