Related papers: Two-photon Above Threshold Ionization of Helium
We present a study of multiphoton dissociative ionization from molecules. By solving the time-dependent Schr\"{o}dinger equation for H$_2^+$ and projecting the solution onto double continuum scattering states, we observe the correlated…
The complex Kohn variational method is extended to compute light-driven electronic transitions between continuum wavefunctions in atomic and molecular systems. This development enables the study of multiphoton processes in the perturbative…
By using the B-spline numerical method, we investigate a two-photon double-ionization (TPDI) process of helium in a high-frequency laser field with its frequency ranging from 1.6~a.u. to 3.0~a.u. and the pulse duration ranging from 75 to…
The cross sections for single-electron photo-ionisation in two-electron atoms show fluctuations which decrease in amplitude when approaching the double-ionisation threshold. Based on semiclassical closed orbit theory, we show that the…
Owing to its numerical simplicity, a two-dimensional two-electron model atom, with each electron moving in one direction, is an ideal system to study non-perturbatively a fully correlated atom exposed to a laser field. Frequently made…
We employ the time-dependent R-Matrix (TDRM) method to calculate anisotropy parameters for positive and negative sidebands of selected harmonics generated by two-color two-photon above threshold ionization of argon. We consider odd…
We present a multichannel photoelectron interferometry technique based on trichromatic pulse shaping for unambiguous determination of quantum phases in multiphoton ionization (MPI) of potassium atoms. The colors of the laser field are…
Photoionization cross sections and rate coefficients have been calculated for all bound vibrational levels of the 1s$\sigma_{\mathrm{g}}$ state of H$_{2}^{+}$, HD$^{+}$, and D$_{2}^{+}$. The Born-Oppenheimer approximation is employed in our…
High precision variational calculations in Hylleraas coordinates are presented for all singlet and triplet $P$-states of helium up to principal quantum number $n = 35$ with a uniform accuracy of 1 part in $10^{22}$ for the nonrelativistic…
Despite inherently complex multiphoton dynamics, our observations show that Ba double ionization with an infrared laser (8800-8920 cm^{-1}) resembles a single-photon process; namely, its probability is proportional to the laser intensity.…
A theoretical investigation of the three-photon transition rates $ 2^1P_1\rightarrow 2^1S_0\;,1^1S_0 $ and $ 2^3P_2\rightarrow 2^1S_0\;,1^1S_0 $ for the helium atom is presented. Photon energy distributions and precise values of the…
A theoretical investigation of photoabsorption and photoionization of Fe^{14+} extending beyond an earlier frame transformation R-matrix implementation is performed using a fully-correlated, Breit-Pauli R-matrix formulation including both…
We have studied the radiative decay of the 2s state of one-electron and one-muon ions, where the two-photon mechanism plays an important role. Due to the nuclear size corrections the radiative decay of the 2s state in the electron and muon…
We study nondipole effects in multiphoton ionization of a two-dimensional hydrogen-like atom by a flat-top laser pulse of varied intensity. For this purpose, we solve numerically a two-dimensional Schr\"odinger equation treating a…
Resonance-enhanced multiphoton ionization (REMPI) in potassium atom is investigated within the strong coupling regime using photoelectron momentum imaging techniques. The kinetic energy distribution of the ionized electrons reveals the…
We present ionization probability and line shape calculations for the two-step 3-photon ionization process, $1S \stackrel{2\hbar \omega}{\longrightarrow}2S \stackrel{\hbar \omega}{\longrightarrow}\epsilon P $, of the ground state of…
Autoionization, which results from the interference between direct photoionization and photoexcitation to a discrete state decaying to the continuum by configuration interaction, is a well known example of the important role of electron…
The relativistic theory of above-threshold ionization (ATI) of hydrogen-like atoms in ultrastrong radiation fields, taking into account the photoelectron induced rescattering in the continuum spectrum is developed. It is shown that the…
Engineering multiphoton states is an outstanding challenge with applications in multiple fields, such as quan- tum metrology, quantum lithography or even biological systems. State-of-the-art methods to obtain them rely on post-selection,…
Photoionization of an atom via interatomic correlations to N neighboring atoms may be strongly enhanced due to constructive interference of quantum pathways. The ionization proceeds via resonant photoexcitation of a neighbor atom and…