Photoexcitation and Photoionization Dynamics of Water Photolysis

Abstract

Despite the importance of water photolysis in atmospheric chemistry, its mechanism is not well understood. Two different mechanisms for water photolysis have been proposed. The first mechanism is driven by water photoexcitation, followed by the reaction of the active hydrogen radical with water clusters. The second mechanism is governed by the ionization process. Both photoexcited and photoionized mechanisms are complementary, which is elucidated by using excited-state ab initio molecular dynamics simulations based on complete active space self-consistent field approach and unrestricted Møller-Plesset second-order perturbation theory based Born-Oppenheimer molecular dynamics simulations.

Structure and Bonding in Ionized Water Clusters

“…[1][2][3][4][5][6][7][8][9] The structure of water clusters after exposure to ionizing radiation is also important in a number of fields spanning chemistry, biology and physics, for example in the neutron irradiation of cooling water in a nuclear atomic plant, the damage of living cells by radiation and in the photoreaction of water in the atmosphere. 2,[10][11][12] Furthermore, the OH radicals that can be produced on ionization have been associated with cell death. 13 Several groups have studied ground state cationic water clusters (H 2 O) + n in experiment.…”

Charge Transfer in Excited States: ab initio Molecular Dynamics Simulations

“…In this ES-AIMD simulation, we considered the first singlet excited state (i.e. HOMO-LUMO excitation) [26].…”

“…OH 2 -like water cluster) forms compete [27]. After 500 fs of UMP2-BOMD simulations, an Eigen form is finally created, which is Reprinted with permission from [26]. Copyright 2008 American Chemical Society energetically more favourable.…”

“…This photoexcitation process involving CTTS takes place in four steps: (i) hydration of the acid; (ii) charge transfer to water upon excitation of hydrated acid; (iii) release of the neutral iodine atom; (iv) detachment of the hydrogen radical [26]. The detachment of iodine from excited hydrated hydro-iodic acids is highly exothermic.…”

Structural exploration and properties of (H2O)4+ cluster via ab initi

“…As a microscopic model to study ionized water, cationic water clusters have become a hot research subject in these days. Besides, these kinds of water clusters also have many unique properties compared with their neutral counterparts [9][10][11]. They have drawn much attention from both physical and chemical fields.…”