Effect of low-temperature argon matrices on the IR spectra and structure of flexible N-acetylglycine molecules

S. G. Stepanian, A. Yu Ivanov, L. Adamowicz

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

A study of how the matrix environment impacts the structure and IR spectra of N-acetylglycine conformers. The conformational composition of this compound is determined according to an analysis of the FTIR spectra of N-acetylglycine isolated in low temperature argon matrices. Bands of three N-acetylglycine conformers are identified based on the spectra: one major and two minor. The structure of all observed conformers is stabilized by different intramolecular hydrogen bonds. The Gibbs free energies of the conformers were calculated (CCSD(T)/CBS method), and these energy values were used to calculate conformer population at a temperature of 360 K, of which 85.3% belonged to the main conformer, and 9.6% and 5.1% to the minor conformers. We also determined the size and shape of the cavities that form when the N-acetylglycine conformers are embedded in the argon crystal during matrix deposition. It is established that the most energetically favorable cavity for the planar main conformer is the cavity that forms when 7 argon atoms are replaced. At the same time, bulky minor conformers were embedded into cavities that correspond to 8 removed argon atoms. We calculated the complexation energy between argon clusters and conformers, and the deformation energy of the argon crystal and the N-acetylglycine conformers. The matrix-induced shifts to the conformer oscillation frequency are calculated.

Original languageEnglish (US)
Pages (from-to)1167-1174
Number of pages8
JournalLow Temperature Physics
Volume42
Issue number12
DOIs
StatePublished - Dec 1 2016

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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