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Title: Improved assignments of the vibrational fundamental modes of ortho -, meta -, and para -xylene using gas- and liquid-phase infrared and Raman spectra combined with ab initio calculations: Quantitative gas-phase infrared spectra for detection

Abstract

Xylenes contain a blend of the ortho-, meta-, and para- isomers, and all are abundant contaminants in the ground, surface waters, and air. To better characterize xylene and to better enable its detection, we report high quality quantitative vapor-phase infrared spectra of all three isomers over the 540-6500 cm -1 range. All fundamental vibrational modes are assigned based on these vapor-phase infrared spectra, liquid-phase infrared and Raman spectra, along with density functional theory (DFT), ab initio MP2 and high energy-accuracy compound theoretical model (W1BD) calculations. Both MP2 and DFT predict a single conformer with C 2v symmetry for ortho-xylene, and two conformers each for meta- and para-xylene, depending on the preferred orientations of the methyl groups. For meta-xylene the two conformers have C s and C 2 symmetry, and for para-xylene these conformers have C 2v or C 2h symmetry. Since the relative population of the two conformers is approximately 50% for both isomers and predicted frequencies and intensities are very similar for each conformer, we made an arbitrary choice to discuss the C s conformer for meta-xylene and the C 2v conformer for para-xylene. We report integrated band intensities for all isomers. Using the quantitative infrared data, we determinemore » the global warming potential values of each isomer and discuss potential bands for atmospheric monitoring.« less

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1393745
Report Number(s):
PNNL-SA-124326
Journal ID: ISSN 0022-2860; 453040142
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Molecular Structure; Journal Volume: 1149; Journal Issue: C
Country of Publication:
United States
Language:
English
Subject:
para-xylene; ortho-xylene; meta-xylene; Infrared; Raman spectroscopy; Quantitative

Citation Formats

Lindenmaier, Rodica, Scharko, Nicole K., Tonkyn, Russell G., Nguyen, Kiet T., Williams, Stephen D., and Johnson, Timothy J.. Improved assignments of the vibrational fundamental modes of ortho -, meta -, and para -xylene using gas- and liquid-phase infrared and Raman spectra combined with ab initio calculations: Quantitative gas-phase infrared spectra for detection. United States: N. p., 2017. Web. doi:10.1016/j.molstruc.2017.07.053.
Lindenmaier, Rodica, Scharko, Nicole K., Tonkyn, Russell G., Nguyen, Kiet T., Williams, Stephen D., & Johnson, Timothy J.. Improved assignments of the vibrational fundamental modes of ortho -, meta -, and para -xylene using gas- and liquid-phase infrared and Raman spectra combined with ab initio calculations: Quantitative gas-phase infrared spectra for detection. United States. doi:10.1016/j.molstruc.2017.07.053.
Lindenmaier, Rodica, Scharko, Nicole K., Tonkyn, Russell G., Nguyen, Kiet T., Williams, Stephen D., and Johnson, Timothy J.. Tue . "Improved assignments of the vibrational fundamental modes of ortho -, meta -, and para -xylene using gas- and liquid-phase infrared and Raman spectra combined with ab initio calculations: Quantitative gas-phase infrared spectra for detection". United States. doi:10.1016/j.molstruc.2017.07.053.
@article{osti_1393745,
title = {Improved assignments of the vibrational fundamental modes of ortho -, meta -, and para -xylene using gas- and liquid-phase infrared and Raman spectra combined with ab initio calculations: Quantitative gas-phase infrared spectra for detection},
author = {Lindenmaier, Rodica and Scharko, Nicole K. and Tonkyn, Russell G. and Nguyen, Kiet T. and Williams, Stephen D. and Johnson, Timothy J.},
abstractNote = {Xylenes contain a blend of the ortho-, meta-, and para- isomers, and all are abundant contaminants in the ground, surface waters, and air. To better characterize xylene and to better enable its detection, we report high quality quantitative vapor-phase infrared spectra of all three isomers over the 540-6500 cm-1 range. All fundamental vibrational modes are assigned based on these vapor-phase infrared spectra, liquid-phase infrared and Raman spectra, along with density functional theory (DFT), ab initio MP2 and high energy-accuracy compound theoretical model (W1BD) calculations. Both MP2 and DFT predict a single conformer with C2v symmetry for ortho-xylene, and two conformers each for meta- and para-xylene, depending on the preferred orientations of the methyl groups. For meta-xylene the two conformers have Cs and C2 symmetry, and for para-xylene these conformers have C2v or C2h symmetry. Since the relative population of the two conformers is approximately 50% for both isomers and predicted frequencies and intensities are very similar for each conformer, we made an arbitrary choice to discuss the Cs conformer for meta-xylene and the C2v conformer for para-xylene. We report integrated band intensities for all isomers. Using the quantitative infrared data, we determine the global warming potential values of each isomer and discuss potential bands for atmospheric monitoring.},
doi = {10.1016/j.molstruc.2017.07.053},
journal = {Journal of Molecular Structure},
number = C,
volume = 1149,
place = {United States},
year = {Tue Jul 25 00:00:00 EDT 2017},
month = {Tue Jul 25 00:00:00 EDT 2017}
}