Coupled cluster anharmonic force fields, spectroscopic constants, and vibrational energies of AIF3 and SiF3+

AbstractThe dipole-bound excited state of the methylene nitrile anion (CH2CN−) has been suggested as a candidate carrier for a diffuse interstellar band (DIB) at 803.8 nm. Its corresponding radical has been detected in the interstellar medium (ISM), making the existence for the anion possible. This work applies state-of-the-art ab initio methods such as coupled cluster theory to reproduce accurately the electronic excitations for CH2CN− and the similar methylene enolate anion, CH2CHO−. This same approach has been employed to indicate that 19 other anions may possess electronically excited states, five of which are valence in nature. Concurrently, in order to assist in the detection of these anions in the ISM, work has also been directed towards predicting vibrational frequencies and spectroscopic constants for these anions through the use of quartic force fields (QFFs). Theoretical rovibrational work on anions has thus far included studies of CH2CN−, C3H−, and is currently ongoing for similar systems.

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DFT anharmonic force field, and spectroscopic constants for phosphaethene, CH2PH

Main Group Chemistry ◽

10.3233/mgc-170237 ◽

2017 ◽

Vol 16 (3) ◽

pp. 207-216 ◽

Cited By ~ 1

Author(s):

Wei-Xiu Pang ◽

Hong-Ye Wu ◽

Jian-Jun Zhao ◽

Yi Lu ◽

Yun-Bin Sun

Keyword(s):

Force Field ◽

Spectroscopic Constants ◽

Anharmonic Force

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Spectroscopic constants and anharmonic force field of dithioformic acid and its isomers: a theoretical study

10.21203/rs.3.rs-1094711/v1 ◽

2021 ◽

Author(s):

Weixiu Pang ◽

Xiaomin Song ◽

Yunbin Sun ◽

Meishan Wang

Keyword(s):

Force Field ◽

Dipole Moments ◽

Molecular Structures ◽

Basis Sets ◽

Astronomical Observation ◽

Spectroscopic Constants ◽

Fundamental Frequencies ◽

Correlation Consistent ◽

Consistent Basis ◽

Anharmonic Force

Abstract The potential astronomical interest dithioformic acid (trans-HC(=S)SH) exists five isomers and has received considerable attention of astronomical observation in recent years. The different positions of H atoms of five isomers lead to diverse point groups, dipole moments, and spectroscopic constants. The anharmonic force field and spectroscopic constants of them are calculated using CCSD(T) and B3LYP employing correlation consistent basis sets. Molecular structures, dipole moments, rotational constants, and fundamental frequencies of trans-HC(=S)SH are compared with the available experimental data. The B3LYP/Gen=5 and CCSD(T)/Gen=Q results can reproduce them well. Molecular structures, dipole moments, relative energies, spectroscopic constants of cis-HC(=S)SH and dithiohydroxy carbene (DTHC) are also calculated. The new data obtained in this study are expected to guide the future high resolution experimental work and to assist astronomical search for CH2S2.

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General derivative relations for anharmonic force fields

Molecular Physics ◽

10.1080/002689796173138 ◽

1996 ◽

Vol 89 (5) ◽

pp. 1213-1221 ◽

Cited By ~ 50

Author(s):

WESLEY D. ALLEN ◽

ATTILA G. CSÁSZÁR ◽

VIKTOR SZALAY ◽

IAN M. MILLS

Keyword(s):

Force Fields ◽

Anharmonic Force

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