•A model of localized wave packets with valence-bond coupling is presented.•Accurate potential energy curves for LiH molecule were obtained and analyzed.•Electron dynamics and high-harmonic spectra induced by laser pulse were studied.A model of localized electron wave packets (WPs) with variable position and width (floating and breathing) that are spin-coupled as per the valence-bond theory is presented. It produces accurate potential energy curves of LiH in the ground singlet and triplet states. Quantization in a mean-field approximation of the motion of a WP that corresponds to the Li 2s electron generates semi-quantitative potential energy curves of low energy excited states. Real-time semiquantal dynamics of the WP induced by an intense laser pulse gives high-harmonic generation spectra that capture qualitative features of a higher-level wave function calculation.Download high-res image (177KB)Download full-size image

A simple wave packet (WP) modeling of electrons in chemical bonding is examined. It is found that floating and breathing minimal Gaussian WPs with fully non-orthogonal perfect-pairing valence-bond spin coupling yield the ground state potential energy surfaces of LiH, BeH2, CH2, and H2O molecules of comparable quality to a high-level ab initio electron-correlated calculations. A simple form of core pseudo-potential with two parameters is shown to give proper modeling of core–valence interactions.Graphical abstractHighlights► We examine a simple wave packet modeling of electrons in chemical bonding. ► In particular, we employ floating and breathing minimal Gaussian wave packets. ► The antisymmetry is dealt with by non-orthogonal perfect-pairing valence-bond theory. ► The model is found to give accurate potential energy surfaces of small molecules. ► A simple core pseudo-potential properly models core–valence interactions.