Complex absorbing potentials for stark resonances

In this work, we study the problem in calculation of Stark resonances by using complex absorbing potentials (CAPs), and its solutions. The motivation of using CAPs for calculating Stark resonances stems from the fact that CAPs can be easily inserted to a large variety of available codes for calculating the electronic structure of molecules and atoms. Our conclusion is that the appropriate CAPs for studying ac/dc Stark resonances are those that are associated with smooth-exterior-scaling (SES) transformations, which rotate the spatial contour of integration into the complex plane. The performance of SES-CAPs vs standard commonly used CAPs in different types of basis sets is investigated.