The Jahn-Teller and pseudo-Jahn-Teller effects in the propyne radical cation.
Phys Chem Chem Phys
; 24(27): 16522-16537, 2022 Jul 13.
Article
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| ID: mdl-35786726
The Jahn-Teller (JT) and pseudo-Jahn-Teller (PJT) effects in the XÌ2E, Ã2E and BÌ2A1 electronic states of the propyne radical cation are investigated with the aid of ab initio quantum chemistry calculations and first principles quantum dynamics simulations. For the latter, both time-independent and time-dependent quantum mechanical methods are employed. Standard vibronic coupling theory is used to construct a symmetry consistent vibronic Hamiltonian in a diabatic electronic basis. Taylor series expansion of the elements of the diabatic electronic Hamiltonian is carried out and the parameters that appear in the expansion are derived from the ab initio calculated adiabatic electronic energies. It is found that the JT effect is weak in the XÌ2E state as compared to that in the Ã2E state. Because of large energy separation, the PJT coupling among the JT-split components of the XÌ2E state with the neighboring states is also very weak. However, the PJT coupling of the BÌ2A1 state with the JT split components of the Ã2E state has some impact on the dynamics in the coupled Ã2E-BÌ2A1 electronic states. The vibronic spectrum of each of these states is calculated and compared with the experimental results. The nonradiative internal conversion dynamics of excited cationic states is examined. Interesting comparison is made with the JT and PJT coupling effects in the nuclear dynamics of the XÌ2E-Ã2E-BÌ2B2 electronic states of the isomeric allene radical cation.
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01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
Phys Chem Chem Phys
Ano de publicação:
2022
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Article