TY - JOUR
T1 - CASPT2 Study on the Low-Lying Electronic States of $m$-$C_6H_4F^+_2$  Ion
AU - Yu , Shu-Yuan
AU - Zhang , Cheng-Gen
JO - Journal of Atomic and Molecular Sciences
VL - 2
SP - 171
EP - 177
PY - 2014
DA - 2014/05
SN - 5
DO - http://doi.org/10.4208/jams.090213.112213a
UR - https://global-sci.org/intro/article_detail/jams/8322.html
KW - CASPT2, electronic states, excitation energies, geometries.
AB - <p style="text-align: justify;">Electronic states of the $m$-$C_6H_4F^+_2$ ion were studied by using the CASPT2
and CASSCF methods in conjunction with a contracted atomic natural orbital (ANOL)
basis set. For the five lowest-lying states, geometries and adiabatic excitation energies $(T_0)$ were calculated at the CASPT2 level. The CASPT2 $T_0$ values and CASPT2 $T&#39;_v$ values are in reasonable agreement with the available experimental data. The assignments
of the $B,$ $C,$ and $D$ states of the $m$-$C_6H_4F^+_2$ ion were difficult since the three
states are closely lying. Based on the CASPT2 $T_0$ calculations, the $X,$ $A,$ $B,$ $C,$ and $D$ states of the $m$-$C_6H_4F^+_2$ ion were assigned to $1^2A_2,$ $1^2B_1,$ $2^2B_1,$ $1^2A_1,$ and $1^2B_2,$ respectively,
which supports the suggested assignment of the lowest excited state to $^2B_1$ by
Tsuchiya et al. based on their experiments.</p>