Improved ground state and v12 = 1 state rovibrational constants of 13C2D4
| Autor: | J.O. Liew, T.L. Tan, L.L. Ng, Q.Y. Wu |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Physics
010304 chemical physics Infrared Anharmonicity Rotational–vibrational spectroscopy 010402 general chemistry 01 natural sciences Atomic and Molecular Physics and Optics 0104 chemical sciences symbols.namesake Fourier transform 0103 physical sciences symbols Isotopologue Physical and Theoretical Chemistry Atomic physics Hamiltonian (quantum mechanics) Ground state Spectroscopy Basis set |
| Zdroj: | Journal of Molecular Spectroscopy. 354:32-36 |
| ISSN: | 0022-2852 |
| DOI: | 10.1016/j.jms.2018.09.009 |
| Popis: | The rovibrational spectrum of the ν 12 band of isotopologue ethylene (13C2D4) was recorded using the Fourier transform infrared (FTIR) spectrometer with an unapodized resolution of 0.0019 cm−1 in the 1000–1140 cm−1 region. From the analysis of this A-type band, the v 12 = 1 state rovibrational constants up to four quartic terms (ΔJ, ΔK, δJ, δK) were improved from previous work and a sextic term was derived for the first time. A total of 2403 infrared transitions were fitted using the Watson's A-reduced Hamiltonian in the Ir representation with a root-mean-square (rms) deviation of 0.00026 cm−1. The band centre of the ν 12 band of 13C2D4 was found to be 1069.969827(13) cm−1. The ground state rotational constants (B, and C) and the centrifugal distortion constants (ΔJ, δJ, δK) were improved with higher accuracy while a sextic term was obtained for the first time through the fitting of 1209 ground state combination differences (GSCDs) derived from the IR transitions of the ν 12 band, together with 504 previously reported GSCDs of the ν 9 band of 13C2D4. The root-mean-square (rms) deviation value of this fit was 0.00027 cm−1. The uncertainty of the measured infrared lines was estimated to be ±0.0003 cm−1. Additionally, equilibrium state rovibrational constants up to five quartic terms, and rotational constants of the ground and v 12 = 1 state were derived from theoretical anharmonic calculations at two different levels of theory, B3LYP and MP2 with the cc-pVQZ basis set, for comparison with the experimental results. These calculated ground state rotational constants of 13C2D4 agreed well within 0.60% of those determined from the GSCD fit in this work. Rotational constants (A, B, and C) of the v 12 = 1 state of 13C2D4 were also calculated using B3LYP/cc-pVQZ and MP2/cc-pVQZ levels with an agreement of 0.56% or less to those derived experimentally. |
| Databáze: | OpenAIRE |
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