All-electron, density-functional-based method for angle-resolved tunneling ionization in the adiabatic regime
Imam S. Wahyutama, Denawakage D. Jayasinghe, François Mauger, Kenneth A. Lopata, Mette B. Gaarde, Kenneth J. Schäfer
Abstract
We develop and test a method that integrates many-electron weak-field asymptotic theory (ME-WFAT) [O. I. Tolstikhin, L. B. Madsen, and T. Morishita, Phys. Rev. A 89, 013421 (2014)] in the integral representation (IR) into the density-functional-theory (DFT) framework. In particular, we present modifications of the integral formula in the IR ME-WFAT to incorporate the potential terms unique to DFT. By solving an adiabatic rate equation for the angle-resolved ionization yield in our DFT-based ME-WFAT method, we show that the results are in excellent agreement with those of real-time time-dependent density-functional-theory (TDDFT) simulations for NO, OCS, $\mathrm{C}{\mathrm{H}}_{3}\mathrm{Br}$, and $\mathrm{C}{\mathrm{H}}_{3}\mathrm{Cl}$ interacting with one- and two-color laser fields with a fundamental wavelength of 800 nm. This agreement is significant because the WFAT calculations take only a small fraction of the time of full TDDFT calculations. These results suggest that in the wavelength region commonly used in strong-field experiments (800 nm and longer), our DFT-based WFAT treatment can be used to rapidly screen for the ionization properties of a large number of molecules as a function of alignment or orientation between the molecule and the strong field.