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Time‐Dependent Density Functional Theory Molecular Dynamics Simulations of Liquid Water Radiolysis
Author(s) -
Tavernelli Ivano,
Gaigeot MariePierre,
Vuilleumier Rodolphe,
Stia Carlos,
Hervé du Penhoat MarieAnne,
Politis MarieFrançoise
Publication year - 2008
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.200800177
Subject(s) - ionization , molecular orbital , chemistry , atomic physics , density functional theory , atomic orbital , dissociation (chemistry) , molecular dynamics , coulomb explosion , molecule , molecular orbital theory , molecular physics , electron , chemical physics , computational chemistry , physics , ion , organic chemistry , quantum mechanics
The early stages of the Coulomb explosion of a doubly ionized water molecule immersed in liquid water are investigated with time‐dependent density functional theory molecular dynamics (TD–DFT MD) simulations. Our aim is to verify that the double ionization of one target water molecule leads to the formation of atomic oxygen as a direct consequence of the Coulomb explosion of the molecule. To that end, we used TD–DFT MD simulations in which effective molecular orbitals are propagated in time. These molecular orbitals are constructed as a unitary transformation of maximally localized Wannier orbitals, and the ionization process was obtained by removing two electrons from the molecular orbitals with symmetry 1 B 1 , 3 A 1 , 1 B 2 and 2 A 1 in turn. We show that the doubly charged H 2 O 2+ molecule explodes into its three atomic fragments in less than 4 fs, which leads to the formation of one isolated oxygen atom whatever the ionized molecular orbital. This process is followed by the ultrafast transfer of an electron to the ionized molecule in the first femtosecond. A faster dissociation pattern can be observed when the electrons are removed from the molecular orbitals of the innermost shell. A Bader analysis of the charges carried by the molecules during the dissociation trajectories is also reported.