In this article, we review state-of-the-art methods for computing vibrational energies of
polyatomic molecules using quantum mechanical, variationally-based approaches. We …

The paper describes methods and fast computational algorithm for building effective
Hamiltonians in molecular physics using perturbative approach. Separations of fast and …

Intramolecular vibrational energy redistribution (IVR) impacts the dynamics of reactions in a
profound way. Theoretical and experimental studies are increasingly indicating that …

By using exponential activation functions with a neural network (NN) method we show that it
is possible to fit potentials to a sum-of-products form. The sum-of-products form is desirable …

We present a contracted basis-iterative method for calculating numerically exact vibrational
energy levels of methane (a 9D calculation). The basis functions we use are products of …

We propose new methods for using contracted basis functions in conjunction with the
Lanczos algorithm to calculate vibrational (or rovibrational) spectra. As basis functions we …

Transition state theory is extended straightforwardly to treat nonadiabatic processes and
applied to study the rate constant of the spin-forbidden reaction CH (2 Π)+ N 2→ HCN+ N (4 …

Anharmonic vibrational states of semirigid polyatomic molecules are often studied using the
second-order vibrational perturbation theory (VPT2). For efficient higher-order analysis, an …

We present a numerically exact calculation of rovibrational levels of a five-atom molecule.
Two contracted basis Lanczos strategies are proposed. The first and preferred strategy is a …

We present a symmetry-adapted Lanczos method that uses projection operators to calculate
energy levels with different symmetries from a single sequence of matrix–vector products …