Collision-induced electronic energy transfer from v=0 of the E(0g+) ion-pair state in I2: Collisions with I2(X)

Abstract

Articles you may be interested inNon-adiabatic transitions from I2( E 0 g + and D 0 u + ) states induced by collisions with M = I2( X 0 g + ) and H2O J. Chem. Phys. 136, 234302 (2012); 10.1063/1.4725541Long-range collisional energy transfer between charge-transfer (ion-pair) states of I 2 , induced by H 2 O and I 2 ( X ) Electric-field-induced g/u mixing of the E0 g + ( 3 P 2 ) and D0 u + ( 3 P 2 ) ion-pair states of jet-cooled I 2 observed using optical triple resonanceThe collision-induced electronic energy transfer that occurs when I 2 in the E(0 g ϩ ) ion-pair electronic state collides with ground electronic state I 2 has been investigated. We prepare I 2 in single rotational levels in vϭ0 of the E state using two-color double resonance laser excitation. The resulting emission spectrum shows that the nearby (⌬T e ϭϪ385 cm Ϫ1 ) D(0 u ϩ ) electronic state is populated. The cross section for collision-induced E→D energy transfer is found to be 18Ϯ3 Å 2 . A range of D state vibrational levels are populated, consistent with a model in which overlap between the initial and final vibrational wave functions is important, but modulated by propensities for small vibrational energy gaps and those energy gaps that are closely matched to the vϭ0→vϭ1 energy separation in the I 2 (X) collision partner.

The influence of amplified spontaneous emission in collisional energy transfer studies exemplified by to transfer in I2

“…X0 þ g (aa) emission observed following excitation of E0 þ g ð 3 P 2 Þ ðv ¼ 0Þ under ASE conditions has a Gaussian envelope characteristic of emission from (v = 0). Under non-ASE conditions the spectrum contains emission from (v = 0-5) of the D0 þ u ð 3 P 2 Þ state [2]. We have reproduced both the ASE and non-ASE spectra.…”

“…ASE transfer cannot explain this discrepancy as it will lead to an increase rather than a decrease in the rate constant, the reverse of the reported observations. In addition, Fecko et al [2] reported a rate constant for transfer from E0 þ g ð 3 P 2 Þ ðv ¼ 0Þ under non-ASE conditions of only 4 Â 10 À11 cm 3 s À1 . This discrepancy may, as suggested by Bibinov et al [4], be down to the response function of the detector system being accounted for in their experiment but not in the other two.…”

“…The transfer goes predominantly to the D0 þ u ð 3 P 2 Þ state as a consequence of the large transition dipole between the two. In the case of transfer from (v = 0) of the E0 þ g ð 3 P 2 Þ state, it was shown that the vibrational level distribution in the D0 þ u ð 3 P 2 Þ state was determined by a combination of the energy mismatch and the FCFs [2]. In contrast, transfer from (v = 8-55) of the E0 þ g ð 3 P 2 Þ state was reported to be determined almost uniquely by the energy mismatch effect with practically no correlation with the FCFs [3][4][5][6].…”

Theoretical and experimental studies of collision-induced electronic energy transfer from v=–3 of the E(g+) ion-pair state of Br2: Collisions with He and Ar

“…[10][11][12][13] Double resonance excitation prepares bromine molecules in a single vibrational level of the E electronic state. [10][11][12][13] Double resonance excitation prepares bromine molecules in a single vibrational level of the E electronic state.…”

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] These studies have focused on the dynamics that accompany the collisions of I 2 following excitation to the E͑0 g + ͒ ion-pair ͑IP͒ state and document an important model system for examining nonadiabatic processes in molecules with dense rovibronic energy levels. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] These studies have focused on the dynamics that accompany the collisions of I 2 following excitation to the E͑0 g + ͒ ion-pair ͑IP͒ state and document an important model system for examining nonadiabatic processes in molecules with dense rovibronic energy levels.…”