A transferable valence force field for polyatomic molecules. A scheme for glycolic acid and methyl glycolate

Hollenstein, H.; Schär, R.W.; Schwizgebel, N.; Grassi, G.; Günthard, Hs. H.

doi:10.1016/0584-8539(83)80138-x

Cited by 42 publications

(99 citation statements)

References 18 publications

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“…The OH stretching region of the spectrum shows one strong band at 3,566 cm −1 and weak bands at 3,675 and 3,478 cm −1 . These bands resemble to the OH stretching vibrations of two low energy conformers (SSC and AAT) of the matrix isolated glycolic acid observed by infrared spectroscopy . Observed Raman bands in the OH stretching region were systematically shifted approximately 5 cm −1 to the higher wavenumbers from the infrared absorptions of corresponding vibrational bands.…”

Section: Resultssupporting

confidence: 69%

“…The solid rare gas matrices are optically transparent from vacuum ultraviolet to far infrared, so photo‐induced processes as well as optical detection of trapped species can be done in wide spectral regions . The vibrational spectroscopy of SSC conformer is characterized in solid argon and nitrogen matrices . Due to their low population at room temperature, only the signatures of the weak vibrational bands of the GAC and AAT conformers are observed after the deposition of gaseous mixture onto low‐temperature substrate.…”

Section: Introductionmentioning

confidence: 99%

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High vibrational overtone excitation‐induced conformational isomerization of glycolic acid in solid argon matrix

Ahokas

Kosendiak

Krupa

et al. 2018

J Raman Spectroscopy

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The high overtone‐induced isomerization of glycolic acid in a low‐temperature argon matrix was investigated using Raman spectroscopy. The Raman spectrum of glycolic acid is presented, and the spectral assignment is supported by vibrational anharmonic calculations. The high overtone excitation of the lowest energy conformer (SSC) at 532 nm induced direct conformational isomerization to higher energy conformers (GAC and AAT). Furthermore, upon excitation at 532 nm GAC and AAT isomerized back to SSC and photo‐induced equilibrium was observed between the conformers. Kinetic model was used to describe the observed isomerization and isomerization rate constants were obtained. No experimental evidence of isomerization between GAC and AAT nor other higher energy conformers were observed.

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Section: Resultssupporting

confidence: 69%

Section: Introductionmentioning

confidence: 99%

High vibrational overtone excitation‐induced conformational isomerization of glycolic acid in solid argon matrix

Ahokas

Kosendiak

Krupa

et al. 2018

J Raman Spectroscopy

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“…Among the methyl a-hydroxy carboxylates, methyl glycolate (MGly) and methyl a-hydroxy-isobutyrate (MHIb) have been the most studied species, having already been the subject of detailed structural, thermodynamic and vibrational analysis, both for the isolated molecule and in the condensed phases [13][14][15][16][17][18]. Matrix isolation infrared spectroscopy studies previously undertaken on these two compounds in our laboratory allowed the identification and characterization, in both cases, of two different conformers 1 SsC and GskC, which were also shown to be present in the gaseous phase [13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Matrix isolation FTIR spectroscopic and theoretical study of methyl lactate

Borba

Gómez‐Zavaglia

Lapiński

et al. 2004

Vibrational Spectroscopy

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Methyl lactate [CH(CH 3)OHC(¼O)OCH 3 ] conformational space was investigated by extensive DFT/B3LYP/6-311þþG(d,p) and MP2/6-31þþG(d,p) calculations and matrix-isolation FTIR spectroscopy in argon and xenon matrices. From the seven different conformers predicted by the calculations, two forms (the most stable conformers yielded by the calculations: SsC and GskC, where the letters refer to the conformations assumed by the HOCC, OCC¼O and O¼COC dihedrals, respectively) were observed and characterized spectroscopically. Conformer interconversion pathways were also theoretically investigated. The low calculated barrier associated with the G 0 sk 0 C ! GskC conversion ($1 kJ mol À1) explains the absence of the third most stable form (G 0 sk 0 C) of methyl lactate in low-temperature matrices. Deposition of methyl lactate at different temperatures, together with the theoretical data, aided to the full assignment of the observed spectra. #

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“…Our experimentally determined fre quency data were not sufficient to determine the 300 force constants, and thus a number of constraints were imposed on the force field. The scheme of constraints used for the present molecule is very similar to that proposed by Hollenstein and Günthard [6,29], The following criteria are shomewhat specific for the glycine molecule: ■ Glycin i) Since the NH3 torsional motion would practically not be separated from its neighboring higher frequen cy modes, the interaction constants of At2 with An and 7t(NH3) are taken into consideration.…”

Section: S T R U C T U R E a N D I N Te R N A L C O O R D I N A T E Smentioning

confidence: 99%

“…A choice of initial values of the force constants was carried out both by comparison with structurally related molecules [5,25,29] and by reference to earlier investigations [13,18]. These force constants were reFined simultaneously to fit a total of 307 experimental ly determined frequencies by least-squares iterative procedure.…”

Section: S T R U C T U R E a N D I N Te R N A L C O O R D I N A T E Smentioning

confidence: 99%

An Empirical Potential Function of α-Glycine Derived from Infrared Spectroscopic Data of D-, ¹³C-, ¹⁵N-, and ¹⁸O-Labeled Species

Kakihana

Akiyama

Nagumo

et al. 1988

Zeitschrift Für Naturforschung A

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The infrared spectra (4000-100 cm " 1) of the a-form crystal of glycine (NH 3 -CH, -COO ") and of thirteen isotopic modifications comprising D, 13C, 1SN, and O were measured at 80 and 290 K. Excellent resolution was reached at the low temperature. In the low temperature spectra the fine structure of the nearly degenerate NH3 and ND3 antisymmetric deformational modes and the C02-torsional bands in the vicinity of 200 cm-1 for each of the isotopic molecules, which in the low-frequency region are strongly overlapped by a number of lattice modes, clearly showed up. Based upon the frequency data of the 14 isotopic analogs and the precisely known structure of the molecule, a normal coordinate analysis was carried out. 307 observed frequencies were utilized to derive a new empirical valence force field reduced to a set of 50 force constants by a number of restrictive assumptions. The resulting force field reproduced the 307 frequencies with a root-meansquare deviation of 3.32 cm-1. This force field emphasizes the importance of interaction force constants of the in-plane C 02-rocking and C 02-deformational coordinates with the CH2-twisting coordinate, which can come form a significant deviation of this molecule from an ideal Cs-symmetry. The composition of normal vibrations from generally accepted local-symmetry coordinates is given in terms of the potential energy distribution (PED). The PED results indicate that almost all the normal modes below 1600 cm' 1 are extensively intermixed group modes, thus precluding a simple normal vibrational decription. Interestingly the PED description for several vibrations associated with the NHj -CH2 -C fragment exhibits strong mixing between quasi-,4' symmetric and -A" antisymmetric coordinates with respect to a pseudo molecular symmetry (CCN) plane in this molecule.

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A transferable valence force field for polyatomic molecules. A scheme for glycolic acid and methyl glycolate

Cited by 42 publications

References 18 publications

High vibrational overtone excitation‐induced conformational isomerization of glycolic acid in solid argon matrix

High vibrational overtone excitation‐induced conformational isomerization of glycolic acid in solid argon matrix

Matrix isolation FTIR spectroscopic and theoretical study of methyl lactate

An Empirical Potential Function of α-Glycine Derived from Infrared Spectroscopic Data of D-, ¹³C-, ¹⁵N-, and ¹⁸O-Labeled Species

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A transferable valence force field for polyatomic molecules. A scheme for glycolic acid and methyl glycolate

Cited by 42 publications

References 18 publications

High vibrational overtone excitation‐induced conformational isomerization of glycolic acid in solid argon matrix

High vibrational overtone excitation‐induced conformational isomerization of glycolic acid in solid argon matrix

Matrix isolation FTIR spectroscopic and theoretical study of methyl lactate

An Empirical Potential Function of α-Glycine Derived from Infrared Spectroscopic Data of D-, 13C-, 15N-, and 18O-Labeled Species

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An Empirical Potential Function of α-Glycine Derived from Infrared Spectroscopic Data of D-, ¹³C-, ¹⁵N-, and ¹⁸O-Labeled Species