Multiphoton ionization of magnesium in a Ti-sapphire laser field

Abstract

In this paper we report the theoretical results obtained for partial ionization yields and the above-threshold ionization (ATI) spectra of Magnesium in a Ti:sapphire laser field (804 nm) in the range of short pulse duration (20-120 fs). Ionization yield, with linearly polarized light for a 120 fs laser pulse, is obtained as a function of the peak intensity motivated by recent experimental data [9]. For this, we have solved the time-dependent Schrödinger equation nonperturbatively on a basis of discretized states obtained with two different methods; one with the two-electron wavefunction relaxed at the boundaries, giving a quadratic discretized basis and the other with the two-electron wavefunction expanded in terms of Mg + -orbitals plus one free electron allowing the handling of multiple continua (open channels). Results, obtained with the two methods, are compared and advantages and disadvantages of the open-channel method are discussed.PACS. 3 2.80.Rm Multiphoton ionization and excitation to highly excited states (e.g., Rydberg states)

Ionization in elliptically polarized pulses: Multielectron polarization effects and asymmetry of photoelectron momentum distributions

“…Simultaneously, their polarizabilities are high and substantially different from those of the corresponding ions. We perform our simulations for Mg since multiphoton ionization of this atom has already attracted attention in experiment [79][80][81][82][83] and theory [84][85][86][87][88]. For Mg, I p = 0.28 a.u., α N = 71.33 a.u., and α I = 35.00 a.u., and at the wavelength of 800 nm, our simulation technique is applicable at the intensities of 2.35 × 10 13 −1.0 × 10 14 W/cm 2 , for which the Keldysh parameter is γ = 2.0 − 1.0.…”

Polarization effects in above-threshold ionization with a mid-infrared strong laser field

“…The adopted long-wavelength laser (∼2000 nm) implies that the quasistatic field approximation can be well satisfied, which is particularly suited for applying the semiclassical model. We choose Mg for the following reasons: firstly, MPI of Mg has already attracted significant attention in experiment [35][36][37][38][39] and theory [40][41][42][43], whereas there is a lack of investigation on TI of Mg; secondly, after the first electron is released, the remaining Mg ion has a large static polarizability and the second electron will be easily influenced by the laser field, which provides an appropriate system for studying the electron dynamics beyond the SAE picture. We focus on the low-energy part of the PES.…”

Multiphoton ionization through the triplet states of Mg by linearly and circularly polarized laser pulses

“…Xenakis and co-workers [12] investigated multiphoton ionization of Mg using 150 fs laser pulses at the wavelength of 400 nm for the peak laser intensities of up to 6 × 10 13 W/cm 2 . Gillen and co-workers [13,14] measured the ionization yield for single and double ionization of Mg exposed to the 800 nm, 120 fs Ti:sapphire laser pulses for the peak intensities of 10 12 − 10 13 W/cm 2 , which was followed by the theoretical analysis [15]. Liontos and his co-workers [16] investigated single and double ionization of Mg by Nd:YAG laser pulses with a ns duration for peak intensities up to 10 12 W/cm 2 .…”