Dynamic signatures of electronically nonadiabatic coupling in sodium hydride: a rigorous test for the symmetric quasi-classical model applied to realistic, ab initio electronic states in the adiabatic representation

Abstract

Sodium hydride (NaH) in the gas phase presents a seemingly simple electronic structure making it a potentially tractable system for the detailed investigation of nonadiabatic molecular dynamics from both computational...

Interexcited State Photophysics I: Benchmarking Density Functionals for Computing Nonadiabatic Couplings and Internal Conversion Rate Constants

“…NACMEs are a measure of the mixing between the adiabatic, or Born–Oppenheimer, electronic states with the nuclear motions, − and appear throughout quantum chemistry. More typically associated with excited state dynamics − and conical intersections, − NACMEs are also important in describing nonradiative relaxation ,− from first principles.…”

“…However, this methodology was restricted to ground state transitions. The implementation by Send and Furche fixed this issue, and is one of the most commonly employed methodologies within the time-dependent density functional theory (TDDFT) framework in quantum chemical packages, such as the Gaussian16 , Turbomole , and Molpro software packages. − By relating the derivative coupling to a residue from linear response theory, which reduces down to the exact expression derived by Chernyak and Mukamel, various cheap treatments to a very expensive problem were developed, with accuracy directly related to the exchange-correlation potential. ,,, …”

“…20−22 By relating the derivative coupling to a residue from linear response theory, which reduces down to the exact expression derived by Chernyak and Mukamel, various cheap treatments to a very expensive problem were developed, with accuracy directly related to the exchange-correlation potential. 7,8,23,24 Following this advent, numerous other methods to approach this problem were proposed. 6,7,23−30 Of course one can always use a multiconfigurational theory such as the complete active space self-consistent field theory (CASSCF) and compute the coupling directly using state-averaged gradients as in the Molpro or Bagel software packages.…”

Nonadiabatic wave packet dynamics and predissociation resonances in sodium hydride

“…Different grid sizes, ranging from 15 Å up to 40 Å, were used to describe the wave packet dynamics and resonance states. The Hamiltonian, including nonadiabatic and time-dependent couplings, is given by 5,11 Ĥ ¼…”

“…1 The potential energy surfaces (PESs) and nonadiabatic couplings are computed in the adiabatic formalism using quantum chemical methodology, whereas the wave packet simulations of the nuclear dynamics normally are performed in the diabatic representation, necessitating an adiabatic to diabatic transformation. 4 In a recent study Talbot et al 5 computed the accurate PES and nonadiabatic couplings for the sodium hydride (NaH) molecule. The potential energy surfaces and first-order derivative couplings were computed using equation-of-motion coupled cluster theory with single and double excitations (EOM-EE-CCSD), with core-valence polarized basis functions.…”