Theoretical chemistry could be seen as a bridge from the real physics of the physicists to the
real chemistry of the experimental chemists. We hence expect that any measurable property …

A quantum mechanical equation H Ψ= E Ψ is composed of three components, viz.,
Hamiltonian H, wave function Ψ, and property E (λ), each of which is confronted with …

Developments during the last two decades in nuclear motion theory made it possible to
obtain variational solutions to the time-independent, nuclear-motion Schrödinger equation of …

A black-box-type algorithm is presented for the variational computation of energy levels and
wave functions using a (ro) vibrational Hamiltonian expressed in an arbitrarily chosen body …

A flexible protocol, applicable to semirigid as well as floppy polyatomic systems, is
developed for the variational solution of the rotational–vibrational Schrödinger equation. The …

The high accuracy ab initio adiabatic potential energy surfaces (PESs) of the ground
electronic state of the water molecule, determined originally by Polyansky et al [Science 299 …

H 3+⁠. The underlying Born–Oppenheimer electronic structure computations used
optimized explicitly correlated shifted Gaussian functions. The surfaces include diagonal …

Publisher Summary This chapter discusses the computation of complete rotational–
vibrational spectra of small molecules. Neither experiments nor first-principles computations …

An effective and general algorithm is suggested for variational vibrational calculations of N-
atomic molecules using orthogonal, rectilinear internal coordinates. The protocol has three …

The analysis and modeling of high-resolution spectra of nonrigid molecules require a
specific Hamiltonian and group-theoretical formulation that differs significantly from that of …