Frequency dependent hyperpolarizability and two photon excitations in hydrogen atom confined under classical plasma environment

Publication date: Available online 7 November 2019Source: Physics Letters AAuthor(s): Sukhamoy Bhattacharyya, Prasanta K. Mukherjee, Burkhard FrickeAbstractFrequency dependent dipole hyperpolarizability of hydrogen atom confined under classical plasma is estimated using nonlinear response theory under a monochromatic electromagnetic field. The screened Coulomb potential is used to model the classical plasma. Time-dependent variation perturbation theory with Slater basis is applied for the first time for such an analysis. As an offshoot, two photon excitations are obtained from the poles of frequency dependent hyperpolarizability. We have specifically studied two photon excited states 2s,3s/3d and 4s/4d from the ground 1s state of H atom. The positions and radial density profiles of two photon excited states of free H atom are in excellent agreement with experimental and analytical results. The accidental degeneracy above principal quantum number n=2 is lifted systematically with respect to increased screening parameters. The results are expected to be important for different nonlinear optical processes like the Kerr effect, degenerate four wave mixing, harmonic generation etc. under external confinement.
Source: Physics Letters A - Category: Physics Source Type: research