Vibrational effects on electron-impact valence excitations of SF6

Vibrational effects on generalized oscillator strengths of ammonia

“…To investigate the influence of nuclear dynamics, the GOS profiles for transitions to three lowest excited singlet-states were calculated including the effects of molecular vibration with the wavefunctions at the equation-of-motion coupled-cluster singles and doubles (EOM-CCSD) level. The theoretical method used in this work has proven to be successful in studies of vibrational effects on electronic excitations in polyatomic molecules [25][26][27][28][29][30]. Comparison of our present calculations with the experiment of Chen et al [16] reveals that the vibrational level dependence of the GOS profile for the à ← X transition is mainly originated in the distortion of electronic wavefunctions induced by outof-plane bending vibration.…”

Generalized oscillator strengths of low-lying electronic excitations in acetylene

“…The EOM-CCSD method has been known for its ability of accurate and wellbalanced description of electronic excited states. Since recent studies have shown that molecular vibration may appreciably affect GOS profiles of polyatomic molecules [35][36][37][38][39], its influence has been taken into account in the calculation.…”

Theoretical Study of Valence Shell Excitation by Electron Impact in CCl4

“…may be ascribed, at least partly, to the failure of the Born approximation, which has often been observed at large momentum transfer. , On the other hand, it is unlikely that the disagreement at K 2 < ∼1 a.u. can be fully attributed to contributions from the second and higher Born terms since theoretical calculations based on the Born approximation have shown good agreement with experimental data for various molecules at small K 2 . − Other possible sources of the discrepancy are discussed later.…”

“…The GOS profiles of transitions to low-lying excited singlet-states have been calculated for the molecule at the equation-of-motion coupled-cluster singles and doubles (EOM-CCSD) level and compared with the recent experimental data. The EOM-CCSD method is known to yield accurate excitation energies and has further been shown to give good predictions of GOS profiles. − Here, it should be noted that at momentum transfer close to zero, electronic excitations by electron impact are dominated by dipole transitions, − and owing to the high symmetry of CCl 4 , only a limited number of excited states are accessible from the ground state if the molecular structure is kept rigid at the equilibrium geometry. However, the structural distortion induced by molecular vibrations may lead to considerable contributions from dipole forbidden transitions to GOSs even at small momentum transfer; thus, such vibrational effects are investigated.…”