TY - JOUR
T1 - Rotational spectrum of the Ar–dimethyl sulfide complex
AU - Tatamitani, Yoshio
AU - Sato, Akinori
AU - Kawashima, Yoshiyuki
AU - Ohashi, Nobukimi
AU - LoBue, James M.
AU - Hirota, Eizi
PY - 2009/1/1
Y1 - 2009/1/1
N2 - The rotational spectra of three isotopomers of the Ar-dimethyl sulfide (DMS) complex - normal, 34S, and 13C species - were measured in the frequency region from 3.7 up to 24.1 GHz by Fourier transform microwave spectroscopy. The normal species yielded 43 a-type and 79 c-type transitions. No Ar tunneling splitting was observed, while many transitions were split by the internal rotation of the two methyl tops of the DMS unit. In cases where the K-type splitting was close to that due to methyl internal-rotation, several forbidden transitions were observed that followed b-type selection rules. All of the observed transition frequencies were analyzed simultaneously using a phenomenological Hamiltonian also used in previously published work describing the Ar-dimethyl ether (DME) and Ne-DME complexes. The rotational and centrifugal distortion constants and the potential barrier height to methyl-top internal rotation, V3, were determined. The rotational constants were consistent with an Ar-DMS center of mass (cm) distance of 3.796 (3) Å and a S-cm-Ar angle of 104.8 (2)°. The V3 potential barrier obtained, 736.17 (32) cm-1, was 97.8% of the DMS monomer barrier. By assuming a Lennard-Jones-type potential, the dissociation energy was estimated to be 2.4 kJ mol-1, which was close to the value for Ar-DME, 2.5 kJ mol-1.
AB - The rotational spectra of three isotopomers of the Ar-dimethyl sulfide (DMS) complex - normal, 34S, and 13C species - were measured in the frequency region from 3.7 up to 24.1 GHz by Fourier transform microwave spectroscopy. The normal species yielded 43 a-type and 79 c-type transitions. No Ar tunneling splitting was observed, while many transitions were split by the internal rotation of the two methyl tops of the DMS unit. In cases where the K-type splitting was close to that due to methyl internal-rotation, several forbidden transitions were observed that followed b-type selection rules. All of the observed transition frequencies were analyzed simultaneously using a phenomenological Hamiltonian also used in previously published work describing the Ar-dimethyl ether (DME) and Ne-DME complexes. The rotational and centrifugal distortion constants and the potential barrier height to methyl-top internal rotation, V3, were determined. The rotational constants were consistent with an Ar-DMS center of mass (cm) distance of 3.796 (3) Å and a S-cm-Ar angle of 104.8 (2)°. The V3 potential barrier obtained, 736.17 (32) cm-1, was 97.8% of the DMS monomer barrier. By assuming a Lennard-Jones-type potential, the dissociation energy was estimated to be 2.4 kJ mol-1, which was close to the value for Ar-DME, 2.5 kJ mol-1.
KW - Ar–(CH3)2S complex
KW - Fourier transform microwave spectrum
KW - Internal rotation
KW - Molecular structure
KW - Van der Waals complex
UR - https://digitalcommons.georgiasouthern.edu/chem-facpubs/31
UR - http://dx.doi.org/10.1016/j.jms.2009.05.007
U2 - 10.1016/j.jms.2009.05.007
DO - 10.1016/j.jms.2009.05.007
M3 - Article
SN - 0022-2852
VL - 257
JO - Journal of Molecular Spectroscopy
JF - Journal of Molecular Spectroscopy
ER -