Photochemical reactions may be classified as adiabatic or as diabatic whether the chemical change occurs on the same potential energy surface or not. In the adiabatic cases deexcitation occurs either in the reactant (I) or in the product (II) while in the diabatic case it occurs in between them (III). The potential energy surfaces of polyatomic systems are discussed in relation to photochemistr...

The literature on gas phase nucleophilic substitution reactions at aliphatic carbon has been reviewed. The emphasis has been on journal articles published in the period 1990–2001. The present review outlines our current understanding of concepts such as potential energy surfaces, structure–energy relationships, microsolvation, and dynamical and mechanistic details based on both experimental and...

We report second and third virial coefficients for the system CO2-H2O, calculated via cluster integrals using quantitative molecular models taken from the literature. Considered models include (1) fits to highly accurate ab initio calculations of the potential energy surfaces, and (2) semi-empirical Gaussian Charge Polarizable Models (GCPM). Three-body effects are found to be essential for obta...

In this introductory exploration of the title theme, we treat a positron as a light nucleus and work within the quasimolecule approximation to obtain, for the first time, adiabatic potential energy curves for its scattering by the He atom. We then show that different elastic and inelastic processes that contribute to the total scattering cross section can be rationalized in molecular terms as d...

Electronic Structure Theory describes the motions of electrons in atoms or molecules. Generally this is done in the context of the Born-Oppenheimer Approximation, which says that electrons are so much lighter (and therefore faster) than nuclei that they will find their optimal distribution for any given nuclear configuration. The electronic energy at each nuclear configuration is the potential ...

for the quintet state of the O2„ 3 g − ...–O2„ 3 g − ... dimer Massimiliano Bartolomei, Estela Carmona-Novillo, Marta I. Hernández, José Campos-Martínez, and Ramón Hernandez-Lamoneda Instituto de Matemáticas y Física Fundamental, Consejo Superior de Investigaciones Científicas, Serrano 123, 28006 Madrid, Spain Centro de Investigaciones Químicas, Universidad Autónoma del Estado de Morelos, 62210...

The laser excited, jet-cooled Ã2A′′ 2 − X̃2E′′ 1 electronic spectrum of the cyclopentadienyl radical yields detailed information about the vibronic structure of both its à and X̃ states. A straight-forward assignment of the à vibronic structure is presented. The X̃ state vibronic structure reveals a comprehensive picture of the Jahn-Teller distortion of its potential energy surface. The molecular ...

Ro-vibrational calculations on a recent ab initio potential energy surface for H: (W. Meyer et al., J. Chem. Phys. 84, 891 (1986)) are presented for the isotopomers H,_.D: (n = 0, 1, 2, 3). These calculations employ refinements recently developed for nuclear motion calculations and are thus of very high accuracy. The rotational levels with .I G 4 are fitted to standard vibrationrotation Hamilto...