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Title: Infrared and Raman Spectroscopy from Ab Initio Molecular Dynamics and Static Normal Mode Analysis: The C–H Region of DMSO as a Case Study

Carbon-hydrogen (C-H) vibration modes serve as key probes in the chemical identification of hydrocarbons and in vibrational sum-frequency generation (SFG) spectroscopy of hydrocarbons at the liquid/gas interface. Their assignments pose a challenge from a theoretical viewpoint. Here in this work, we present a detailed study of the C-H stretching region of dimethyl sulfoxide (DMSO) using a new Gaussian basis set- based ab initio molecular dynamics (AIMD) module that we have implemented in the NWChem computational chemistry program. By combining AIMD simulations and static normal mode analysis, we interpret experimental infrared and Raman spectra and explore the role of anharmonic effects in this system. Our anharmonic normal mode analysis of the in-phase and out-of-phase symmetric C-H stretching modes challenges the previous experimental assignment of the shoulder in the symmetric C-H stretching peak as an overtone or Fermi resonance. In addition, our AIMD simulations also show significant broadening of the in-phase symmetric C-H stretching resonance, which suggests that the experimentally observed shoulder is due to thermal broadening of the symmetric stretching resonance.
Authors:
 [1] ;  [2] ;  [3] ;  [2] ;  [3] ;  [1] ;  [4] ;  [1]
  1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
  2. Univ. of Puget Sound, Tacoma, WA (United States). Dept. of Chemistry
  3. Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Physical Sciences Division
  4. Univ. of Minnesota, Minneapolis, MN (United States). Supercomputing Inst. and Chemical Theory Center, Dept. of Chemistry
Publication Date:
OSTI Identifier:
1254566
Report Number(s):
PNNL-SA-109387
Journal ID: ISSN 1520-6106; 48664; KC0301050
Grant/Contract Number:
AC05-76RL01830; SC0008666
Type:
Accepted Manuscript
Journal Name:
Journal of Physical Chemistry. B, Condensed Matter, Materials, Surfaces, Interfaces and Biophysical Chemistry
Additional Journal Information:
Journal Volume: 120; Journal Issue: 8; Journal ID: ISSN 1520-6106
Publisher:
American Chemical Society
Research Org:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); USDOE Office of Science (SC), Workforce Development for Teachers and Scientists (WDTS) (SC-27); USDOE Office of Science (SC), Advanced Scientific Computing Research (ASCR) (SC-21); National Science Foundation (NSF); USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 54 ENVIRONMENTAL SCIENCES; Environmental Molecular Sciences Laboratory