One-, two- and three-photon ionization of calcium

Abstract

One-, two- and three-photon ionization of the calcium atom from its ground state has been analysed in the perturbative regime by studying its electronic structure employing B-spline basis functions in a configuration interaction procedure based on a frozen-core Hartree–Fock approach combined with model potentials. We investigate the photoionization spectrum in the region located between the 4s 2Se and 3d 2De thresholds and focus our attention on the features originating from the excitation of autoionizing states. Good quantitative agreement is obtained with available theoretical and experimental data for one-photon and two-photon ionization. The three-photon excitation of the 1Po and 1Fo series of autoionizing states is also reported.

Two-, three-, and four-photon ionization of Mg in the circularly and linearly polarized laser fields: Comparative study using the Hartree–Fock and model potentials

“…Although there are quite a few theoretical reports for the multiphoton ionization cross sections beyond the single-valence-electron atoms such as Xe, He, Be, Mg, and Ca [4][5][6][7][8][9][10][11][12][13], all of them assumes the LP field. Although theoretical data for the multiphoton ionization cross sections for complex atoms by the CP field would provide complementary information to those by the LP field for the purpose of understanding the multiphoton dynamics, such data are still missing in the literature.…”

Two-color photoionization of calcium using SHG and LED light

“…For experiments where low loading rates are acceptable, a broad-bandwidth radiation source of relatively low power (i.e. far below saturation of the involved transitions) is sufficient, since many transitions of partially overlapping linewidths and broad autoionizing resonances [18,36] are available for the (electric field assisted) excitation into the continuum. We chose to use a high-power UV-LED from Nichia (NCCU001) to achieve loading of single ions, and we designed an optical system tailored to the LED emission characteristics.…”

Multiphoton ionization of the calcium atom by linearly and circularly polarized laser fields

“…Ca have been reported in recent works [9,11,22], we only make a brief description of the method we employ. The field-free one-electron Hamiltonian of Ca + , H a (r), is expressed as:…”

“…For Ca, which is heavier than Be and Mg but still relatively light alkaline-earth-metal atom, the LS coupling is known to give a fair description [7][8][9]11] and hence it is sufficient to label a two-electron state by the following set of quantum numbers: principal, orbital, and spin quantum numbers for each electron, n i l i s i (i = 1, 2), total orbital momentum L, total spin S, total angular momentum J, and its projection M on the quantization axis.…”

“…As for the MPI processes Benec'h and Bachau [11] calculated the one-, two-, and threephoton ionization cross sections of Ca from the ground state with B-spline basis functions and CI procedure, where the FCHF approach and polarization potentials were employed to construct the atomic basis. Regarding the experimental MPI processes of Ca, there are only several works in the literature, all of which involve only ns and ps laser pulses.…”