Hsiang-Shun Chou

Relativistic excitation energies and oscillator strengths including core-polarization effects for the intercombination and resonance transitions in Mg-like ions

Excitation energies and oscillator strengths from the 1S0 ground state to the first 3P10 and 1P10 excited states of Mg-like ions are calculated using the multiconfiguration relativistic random-phase approximation including excitation channels from core electrons. The discrepancies between the relativistic random-phase approximation calculation and experimental results for the intercombination excitation energies and oscillator strengths are much reduced. The excitation energies and oscillator strengths for the resonance transition from the multiconfiguration relativistic random-phase approximation are in excellent agreement with experiment. A substantial part of the discrepancy in the 3P10-1P10 separations is resolved when core excitation channels are taken into account.

Dressed-Atom Multiphoton Analysis of Anomalous Electromagnetically Induced Absorption

A method to interpret probe spectra of driven degenerate atomic systems is discussed. The dressed-atom multiphoton spectroscopy (DAMS) is based on a dressing of the atomic system with the strong coupling field, followed by a perturbative treatment of the probe field interaction. As an example, we apply the DAMS to provide a clear interpretation for anomalous electromagnetically induced absorption (EIA), which cannot be explained by spontaneous transfer of coherence. We show that anomalous EIA arises from quantum interference among competing two-photon transitions and explain the different dependences on the coupling field strength observed for various angular momentum setups.

Core-polarization effects for the (6s2) 1S0 to (6s6p) 3P10, 1P10 transitions in Hg-like ions

Excitation energies and oscillator strengths from the 1S0 ground state to the first 3P10 and 1P10 excited states of Hg-like ions are calculated by using the multiconfiguration relativistic random-phase approximation including excitation channels from core electrons. The discrepancies between the theoretical and experimental results are much reduced for the oscillator strengths but more enhanced for the excitation energies when these core-polarization effects are taken into account.

Core-polarization effects in the 3P1o1P1o separations of Cd- and Hg-like ions☆

Abstract The 3P1o1P1o separations of Cd- and Hg-like ions from the multiconfiguration relativistic random-phase approximation including core-excitation channels are compared with those from other theories and with experiment. The present ab initio results are generally in better agreement with experiment than those from semiempirical theories.

Oscillator strengths and lifetimes of Zn I and Ga II

We have applied the second-order relativistic many-body perturbation theory to calculate the oscillator strengths for the spin-allowed electric-dipole (E1) transitions in Zn I and Ga II. We have studied 11 transitions among the first 12 levels of Zn I and Ga II. Radiative lifetimes of some levels in Zn I and Ga II are also evaluated. In particular, the present study provides the first relativistic calculation for the transitions (4s4p) 3 P o,1,2 → (4p 2 ) 3 P0,1,2 in Zn I whose oscillator strengths are sensitive to the interplay between the relativistic effects and the bound‐continuum correlations. The transition amplitudes obtained in different gauges agree within 2%. The present results agree well with experiment.