The ansatz Ψ= (1+1/2r12)Φ+χ with Φ the bare nuclear (or screened nuclear) wave function and χ expanded in products of one-electron functions is explored for second-order perturbation theory and for variational calculations of the ground state of Helium-like ions.

r12-Dependent terms in the wave function as closed sums of partial wave amplitudes for large l

Explicitly Correlated Electrons in Molecules Christof H€attig, Wim Klopper,* Andreas K€ohn, and David P. Tew Lehrstuhl f€ur Theoretische Chemie, Ruhr-Universit€at Bochum, D-44780 Bochum, Germany Abteilung f€ur Theoretische Chemie, Institut f€ur Physikalische Chemie, Karlsruher Institut f€ur Technologie, KIT-Campus S€ud, Postfach 6980, D-76049 Karlsruhe, Germany Institut f€ur Physikalische Chemie, Johannes Gutenberg-Universit€at Mainz, D-55099 Mainz, Germany School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom

Explicitly correlated electrons in molecules.

The variational method complemented with the use of explicitly correlated Gaussian basis functions is one of the most powerful approaches currently used for calculating the properties of few-body systems. Despite its conceptual simplicity, the method offers great flexibility, high accuracy, and can be used to study diverse quantum systems, ranging from small atoms and molecules to light nuclei, hadrons, quantum dots, and Efimov systems. The basic theoretical foundations are discussed, recent advances in the applications of explicitly correlated Gaussians in physics and chemistry are reviewed, and the strengths and weaknesses of the explicitly correlated Gaussians approach are compared with other few-body techniques.

Theory and application of explicitly correlated Gaussians

Møller-plesset calculations taking care of the correlation CUSP

Classification of Fine Structural Characteristics in Cellulose by Infared Spectroscopy. Use of Potassium Bromide Pellet Technique

Gaussian One‐ and Two‐Electron Wavefunctions

The energy of the ground state of helium is calculated according to the variation method with trial functions formed from a number of different types of linear combinations of Gaussian functions. These functions are compared with respect to a) their convergence towards the exact wave function with increasing number of linear terms, b) the effectiveness of different kinds of correlation functions c) numerical labour.

K. Singer

Papers

Gaussian One‐ and Two‐Electron Wavefunctions

A survey of Gaussian two-electron functions

The kinetics of oxidation by nitrous acid and nitric acid. Part II. Oxidation of formic acid in aqueous nitric acid

The kinetics of oxidation by nitrous acid and nitric acid. Part I. Oxidation of formic acid by nitrous acid

A bromometric method for the determination of formic acid and nitrite