TY - JOUR
T1 - Millimeter-wave spectroscopy of HDC=CH
AU - Hayashi, Masato
AU - Matsubayashi, Hiromu
AU - Ichiyama, Tomohiro
AU - Harada, Kensuke
AU - Tanaka, Keiichi
N1 - Funding Information:
We thank Professor Takehiko Tanaka, emeritus professor of Kyushu University, for his helpful discussion and contribution to this article. This work was supported by the Grant-in-Aid for Scientific Research (Grant Nos. 11440182, 16550018, 17655009, and 18043021) from the Ministry of Education, Science, Culture, and Sports. We (K.T. and K.H.) also thank the International Center of Space Weather Science and Education, Kyushu University, for their financial support. We also thank the Low-temperature Science Center, Kyushu University, for the scientific support.
Publisher Copyright:
© 2019 Author(s).
PY - 2019/11/14
Y1 - 2019/11/14
N2 - Rotational transitions of the mono(β)-deuterated vinyl radical, HDC=CH, produced in a supersonic jet expansion by the ArF excimer laser photolysis, were observed by millimeter-wave spectroscopy. The b-type rotational transitions together with the weak a-type transitions were observed only for the lower component of the tunneling doublet, and no tunneling-rotation transitions connecting the lower and upper components were observed, suggesting that state mixing between the two components is negligibly small. The derived molecular constants such as the A rotational constant, Fermi contact interaction constants, and magnetic dipolar interaction constants indicate that the carrier of the observed spectrum is the trans-form of HDC=CH isomers, where the α-proton is located on the opposite side of the β-deuteron. The present conclusion of the trans-form of HDC=CH was also supported by the ab initio calculation in the CCSD(T)/cc-pVTZ level since the trans-form is calculated to be located by 30.04 cm-1 lower than the cis-form due to the difference in the zero point energy. As a result, the tunneling components in the ground state of HDC=CH behave as two different isomers localized at the trans- and cis-wells of the asymmetric double minimum potential. Observed hyperfine constants for HDC=CH were compared with those for H2C=CH to be consistent with each other.
AB - Rotational transitions of the mono(β)-deuterated vinyl radical, HDC=CH, produced in a supersonic jet expansion by the ArF excimer laser photolysis, were observed by millimeter-wave spectroscopy. The b-type rotational transitions together with the weak a-type transitions were observed only for the lower component of the tunneling doublet, and no tunneling-rotation transitions connecting the lower and upper components were observed, suggesting that state mixing between the two components is negligibly small. The derived molecular constants such as the A rotational constant, Fermi contact interaction constants, and magnetic dipolar interaction constants indicate that the carrier of the observed spectrum is the trans-form of HDC=CH isomers, where the α-proton is located on the opposite side of the β-deuteron. The present conclusion of the trans-form of HDC=CH was also supported by the ab initio calculation in the CCSD(T)/cc-pVTZ level since the trans-form is calculated to be located by 30.04 cm-1 lower than the cis-form due to the difference in the zero point energy. As a result, the tunneling components in the ground state of HDC=CH behave as two different isomers localized at the trans- and cis-wells of the asymmetric double minimum potential. Observed hyperfine constants for HDC=CH were compared with those for H2C=CH to be consistent with each other.
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U2 - 10.1063/1.5126671
DO - 10.1063/1.5126671
M3 - Article
C2 - 31731846
AN - SCOPUS:85075064758
SN - 0021-9606
VL - 151
JO - Journal of Chemical Physics
JF - Journal of Chemical Physics
IS - 18
M1 - 184304
ER -