Probing the Charge-Transfer Potential Energy Surfaces by the Photodissociation of [Ar–N₂]⁺

Abstract

Chemical reaction pathways and product state correlations of gas-phase ion–molecule reactions are governed by the involved potential energy surfaces (PESs). Here, we report the photodissociation dynamics of charge-transfer complex [Ar–N2]+, which is the intermediate of the model system of the Ar+ + N2 → Ar + N2 + reaction. High-resolution recoiling velocity images of photofragmented N2 and N2 + from different dissociation channels exhibit a vibrational state-specific correlation, revealing the nonadiabatic charge-transfer mechanisms upon the photodissociation of [Ar–N2]+. The state-resolved product branching ratios have yielded an accurate determination of the resonant charge-transfer probabilities. This work provides a powerful approach to elucidating the detailed dynamics of chemical events of charge-transfer complex [Ar–N2]+ and to probing the state-to-state charge-transfer PESs.

Photodissociation Dynamics of the [O2–H2O]+ Ionic Complex

“…Although calculations in ref 25 result in a C 2v structure (−0.04 eV) that lies very close to the adopted ground state, as we discussed below, the electronic state diagram with a C s ground in Figure 1 provides a theoretical basis to understand the experimental findings here. Similar to our recent discussion for the case of [Ar−N 2 ] + , 26 a complementary study on dissociation channels (1) and (2) allows us to infer necessary information to understand the photodissociation and charge-transfer dynamics of [O 2 − H 2 O] + .…”

“…Based on the energy conservation rule in a photodissociation reaction, we have where E INT ([O 2 –H 2 O] + ) is the initial internal energy of the parent [O 2 –H 2 O] + , E h ν the photoexcitation energy, D 0 the dissociation energy of the ground state [O 2 –H 2 O] + to a specific product channel, E INT the total internal energy of photofragments, and E avl the total energy available to be partitioned between E TKER and E INT . Similar to our previous studies by the same instrument, ,− the parent ions could be efficiently cooled down to electronically and vibrationally ground state in the cold ion trap, i.e., the term is negligible. For the studied [O 2 –H 2 O] + system, the dissociation energy D 0 correlated with the lowest dissociation limit, i.e., channel (), has been discussed by a number of researchers, − ,, but an accurate determination from experiments is still lacking.…”

“…The CIT-VMI spectrometer used in this study has been described in detail elsewhere , and has been successfully applied to study the photodissociation dynamics of other molecular ions − and ionic complexes . In the present experiment, the [O 2 –H 2 O] + ionic complexes are produced by 300 eV electron impact ionization of a supersonically expanding sample gas that is prepared by mixing the vapor of deionized water with 20% O 2 /He at a pressure of ∼5 bar.…”

Fragment imaging in the infrared photodissociation of the Ar-tagged protonated water clusters H3O+–Ar and H+(H2O)2–Ar

“…This new imaging scheme has been applied to visible/ultraviolet photodissociation reactions to study electronically excited state dynamics. [39][40][41][42][43][44][45][46][47][48][49][50][51][52] Vibrationally excited state dynamics can also be studied by infrared excitation. The first application to infrared photodissociation was for the H 2 O + -Ar complex ion.…”