We present high level ab initio potential energy curves for the M(n+)-RG complexes, where n = 1, 2, RG = rare gas, and M = Be and Mg. Spectroscopic constants have been derived from these potentials, and they generally show very good agreement with the available experimental data. The potentials have also been employed in calculating transport coefficients for M(+) moving through a bath of RG atoms, and the isotopic scaling relationship is examined for Mg(+) in Ne. Trends in binding energies, D(e), and bond lengths, R(e), are discussed and compared to similar ab initio results involving the corresponding complexes of the heavier alkaline earth metal ions. We identify some very unusual behavior, particularly for Be(+)-Ne, and offer possible explanations.

We present high-level ab initio potential energy curves for barium cations and dications interacting with RG atoms (RG = rare gas). These potentials are employed to derive spectroscopic parameters for the Ba(+)-RG and Ba(2+)-RG complexes, and also to derive the transport coefficients for Ba(+) and Ba(2+) moving through a bath of the rare gas. The results are compared to the limited experimental data, which generally show reasonable agreement. We identify a large change in binding energy going from Ba(+)-He and Ba(+)-Ne to Ba(+)-Ar, which is not present in Ba(2+)-RG, and show that this is due to significant dispersion interactions in Ba(+)-RG.

The intramolecular vibrational redistribution (IVR) dynamics following the excitation of a mode in the first electronically excited states of toluene, toluene-d3 and p-fluorotoluene that has predominantly C-CH3 stretching character and an internal energy of ~1200 cm(-1) have been compared using picosecond time-resolved photoelectron imaging spectroscopy as a probe. Temporal changes in the intensities of spectral features in each molecule have enabled IVR lifetimes of 12, 15 and 50 ps, respectively, to be determined. Our measurements show that doorway states are critical in mediating the IVR dynamics in toluene and toluene-d3, and we deduce that these doorway states, which are assigned in the course of this work, are also instrumental in reducing the IVR lifetimes of these molecules relative to p-fluorotoluene.

We present high level ab initio potential energy curves for the M(n+)-RG complexes, where n=1 and 2; RG=He-Rn; and M=Ca, Sr, and Ra. Spectroscopic constants have been derived from these potentials and are compared with a wide range of experimental and previous theoretical data, and good agreement is generally seen. Large changes in binding energy, D(e), and bond length, R(e), between M(+)-He, M(+)-Ne, and M(+)-Ar, also found previously in the analogous Ba(+)-RG complexes [M. F. McGuirk et al., J. Chem. Phys. 130, 194305 (2009)], are identified and the cause investigated; the results shed light on the previous Ba(+)-RG results. These unusual trends are not observed for the dicationic complexes, which behave in a fashion similar to the isoelectronic alkali metal ion complexes. The potentials have also been employed to calculate transport coefficients for M(n+) moving through a bath of rare gas (RG) atoms.

We report electronic spectra of the Au-Xe complex for the first time. The transitions are recorded in the vicinity of the Au atomic 6p<-- 6s transitions. Structured spectra are found close to both the 6(2)P(1/2) and 6(2)P(3/2) states. The former is assigned as a (2)Pi(1/2) state in line with previous work on Au-Ar and Au-Kr; the possible assignment of the second spectrum is discussed. In addition, a large basis set extrapolated RCCSD(T) potential energy curve for the ground state, X(2)Sigma(+), is presented and derived spectroscopic parameters reported. More qualitative calculations are presented for electronically-excited states which arise from the Au(5(2)D) + Xe and Au(6(2)P) + Xe asymptotes, as well as some higher-lying states. The ab initio results are employed in the assignment of the reported spectra.