Autoionization rate constants of zero electron kinetic energy Rydberg states

Highlights: ► Rovibrational autoionization rate constants for diatomic molecules. ► Density matrix formulation based on the model of IBOA. ► Quantum number and energy dependences are studied. - Abstract: We have calculated the vibrational and rotational autoionization rate constants for diatomic molecules H2, N2, and HCl in high Rydberg states by employing the density matrix formulation with the inverse Born–Oppenheimer approximation basis set. The purpose is to simulate the main radiationless processes occurring in zero electron kinetic energy (ZEKE) spectroscopy. The quantum numbers and the energy dependences of the calculated autoionization rate constants are represented as the scaling laws via nonlinear regression. These data provide a suitable starting point for quantitative study of the intricate dynamics involved in ZEKE Rydberg states.