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Title: High-Resolution Infrared Spectra of Spiropentane, C5H8

Abstract

Infrared spectra of spiropentane (C{sub 5}H{sub 8}) have been recorded at a resolution (0.002 cm{sup -1}) sufficient to resolve for the first time individual rovibrational lines. This initial report presents the ground state constants for this molecule determined from the detailed analysis of the {nu}16 (b2) parallel band at 993 cm{sup -1}. In addition, the determination included more than 2000 ground state combination-differences deduced from partial analyses of four other infrared-allowed bands, the {nu}24(e) perpendicular band at 780 cm{sup -1} and three (b2) parallel bands at 1540 cm{sup -1} ({nu}14), 1568 cm{sup -1} ({nu}5+{nu}16), and 2098 cm{sup -1} ({nu}5+{nu}14). In each of the latter four cases, the spectra show complications; in the case of {nu}24, these complications are due to rotational l-type doublings, and in the case of the parallel bands, the spectral complexities are due to Fermi resonance and Coriolis interactions of the upper states with nearby levels. The unraveling of these is underway but the assignment of many of these transitions permit the confident use of the ground state differences in determining the following constants for the ground state (in units of cm{sup -1}): B0 = 0.1394736(2), DJ = 2.458(1) x 10{sup -8}, DJK = 8.28(3) x 10{supmore » -8}. For the unperturbed {nu}16 fundamental, more than 3000 transitions were fit and the band origin was found to be at 992.53793(2) cm{sup -1}. The numbers in parentheses are the uncertainties (two standard deviations) in the value of the last digit of the constants. Surprisingly, the very accurate B0 value measured here is lower than the value (0.1418 cm{sup -1}) calculated from an electron diffraction structure, instead of being higher, as expected. Where possible, the rovibrational results are compared with those computed at the anharmonic level using the B3LYP density functional method with a cc-pVTZ basis set. These too suggest that the electron diffraction results are in question.« less

Authors:
; ; ; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
1029065
Report Number(s):
PNNL-SA-78852
32692; KP1704020; TRN: US201122%%696
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Journal of Molecular Spectroscopy
Additional Journal Information:
Journal Volume: 269; Journal Issue: 1
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; DENSITY FUNCTIONAL METHOD; ELECTRON DIFFRACTION; FERMI RESONANCE; GROUND STATES; INFRARED SPECTRA; ORIGIN; RESOLUTION; SPECTRA; Spiropentane; High-resolution infrared spectrum; Rovibrational constants; DFT study; Anharmonic frequencies; Environmental Molecular Sciences Laboratory

Citation Formats

Price, Joseph E, Coulterpark, K A, Masiello, Tony, Nibler, Joseph W, Weber, Alfons, Maki, Arthur G, and Blake, Thomas A. High-Resolution Infrared Spectra of Spiropentane, C5H8. United States: N. p., 2011. Web. doi:10.1016/j.jms.2011.05.011.
Price, Joseph E, Coulterpark, K A, Masiello, Tony, Nibler, Joseph W, Weber, Alfons, Maki, Arthur G, & Blake, Thomas A. High-Resolution Infrared Spectra of Spiropentane, C5H8. United States. https://doi.org/10.1016/j.jms.2011.05.011
Price, Joseph E, Coulterpark, K A, Masiello, Tony, Nibler, Joseph W, Weber, Alfons, Maki, Arthur G, and Blake, Thomas A. 2011. "High-Resolution Infrared Spectra of Spiropentane, C5H8". United States. https://doi.org/10.1016/j.jms.2011.05.011.
@article{osti_1029065,
title = {High-Resolution Infrared Spectra of Spiropentane, C5H8},
author = {Price, Joseph E and Coulterpark, K A and Masiello, Tony and Nibler, Joseph W and Weber, Alfons and Maki, Arthur G and Blake, Thomas A},
abstractNote = {Infrared spectra of spiropentane (C{sub 5}H{sub 8}) have been recorded at a resolution (0.002 cm{sup -1}) sufficient to resolve for the first time individual rovibrational lines. This initial report presents the ground state constants for this molecule determined from the detailed analysis of the {nu}16 (b2) parallel band at 993 cm{sup -1}. In addition, the determination included more than 2000 ground state combination-differences deduced from partial analyses of four other infrared-allowed bands, the {nu}24(e) perpendicular band at 780 cm{sup -1} and three (b2) parallel bands at 1540 cm{sup -1} ({nu}14), 1568 cm{sup -1} ({nu}5+{nu}16), and 2098 cm{sup -1} ({nu}5+{nu}14). In each of the latter four cases, the spectra show complications; in the case of {nu}24, these complications are due to rotational l-type doublings, and in the case of the parallel bands, the spectral complexities are due to Fermi resonance and Coriolis interactions of the upper states with nearby levels. The unraveling of these is underway but the assignment of many of these transitions permit the confident use of the ground state differences in determining the following constants for the ground state (in units of cm{sup -1}): B0 = 0.1394736(2), DJ = 2.458(1) x 10{sup -8}, DJK = 8.28(3) x 10{sup -8}. For the unperturbed {nu}16 fundamental, more than 3000 transitions were fit and the band origin was found to be at 992.53793(2) cm{sup -1}. The numbers in parentheses are the uncertainties (two standard deviations) in the value of the last digit of the constants. Surprisingly, the very accurate B0 value measured here is lower than the value (0.1418 cm{sup -1}) calculated from an electron diffraction structure, instead of being higher, as expected. Where possible, the rovibrational results are compared with those computed at the anharmonic level using the B3LYP density functional method with a cc-pVTZ basis set. These too suggest that the electron diffraction results are in question.},
doi = {10.1016/j.jms.2011.05.011},
url = {https://www.osti.gov/biblio/1029065}, journal = {Journal of Molecular Spectroscopy},
number = 1,
volume = 269,
place = {United States},
year = {Thu Sep 01 00:00:00 EDT 2011},
month = {Thu Sep 01 00:00:00 EDT 2011}
}