Isomerization reaction between linear AlNC and AlCN including the X 1Σ+ and à 1Π states studied by three-dimensional wave packet propagation.

Excitation transfers between linear AlNC and AlCN via the à (1)Π (1 (1)A", 2 (1)A')-X (1)Σ(+) transition were studied by a wave packet propagation method as applied to a simple system for an isomerization reaction. The photoabsorption and fluorescence spectra calculated in this work are in good agreement with Einstein's A and B coefficients reported in our previous paper [I. Tokue and S. Nanbu, J. Chem. Phys. 124, 224301 (2006)]. In the 2 (1)A'-X (1)Σ(+) excitation of linear AlNC, both isomerization to linear AlCN and dissociation to Al + CN can occur; the probability of both decay channels strongly depends on the vibrational modes of the initial wave packet. The 1 (1)A"-X (1)Σ(+) excitation of linear AlNC results primarily in dissociation with isomerization being found to be a relatively minor phenomenon. For the linear AlCN excitation, vibrational levels above 1000 cm(-1) occur for both isomerization and dissociation. The isomerization of AlNC ↔ AlCN was found to occur after the à (1)Π-X (1)Σ(+) fluorescence of AlNC and AlCN, with even the initial wave packet being made with the vibrational ground level of the à (1)Π state, whereas no dissociation was recognized for any of the cases calculated in this study using lower vibrational levels as initial wave packets. The procedure for wave packet propagation employed in this study is concluded to be very effective for analyzing in detail the reaction dynamics of isomerization for triatomic molecules.