Analysis of resonance structure in the above-threshold ionization photoelectron spectra of magnesium

Abstract

Using high-resolution photoelectron spectroscopy and 120-fs, 800-nm Ti:sapphire laser pulses, we observe and analyze intensity-dependent resonant population of specific intermediate excited states of neutral magne sium atoms and their subsequent photoionization in the laser field. Various participating states are identified using angular-momentum selection rules, partial yields, and angular distributions. Several unexpected results are observed and discussed, including peaks that do not correspond to expected resonant processes, and order-to-order variations in the photoelectron spectra.

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.…”

Experimental Evidence of Above-Threshold Photoemission in Solids

“…The ratio between the three-photon above-threshold and the two-photon Fermi edges is found to be 10 ÿ4 . This value constitutes the only available benchmark for theories aimed at understanding the mechanism responsible for above-threshold photoemission in solids.In recent years a significant effort has been dedicated to the study of above-threshold ionization (ATI) [1][2][3][4][5]. A photoionization process is defined as ATI when the number n of photons of energy h absorbed by an atom to eject one electron is larger than the minimum number m of photons necessary to overcome the ionization potential W ion : mh < nh where m ÿ 1h < W ion < mh.…”

Absolute Ionization Rates of Multielectron Transition Metal Atoms in Strong Infrared Laser Fields

“…The first correlated two-electron phenomenon, nonsequential double ionization in rare gases, can be treated within the SF-SAE picture by considering the recollision of the continuum SAE with the core [2,3]. The strong field ionization of two-electron atoms (Mg and Ca) show perhaps the first hints of deviation from the SF-SAE picture [4,5]. More complex multielectron correlation phenomena, showing a complete failure of the SF-SAE picture, were observed in the strong field ionization of polyatomic molecules in both the adiabatic [6,7] and nonadiabatic [8,9] regimes.…”