Two-photon double ionization of helium in the region of photon energies 42-50 eV
نویسنده
چکیده
We report the total integrated cross-section (TICS) of two-photon double ionization of helium in the photon energy range from 42 to 50 eV. Our computational procedure relies on a numerical solution of the time-dependent Schrödinger equation on a square-integrable basis and subsequent projection of this solution on a set of final states describing two electrons in continuum. Close to the threshold, we reproduce results previously known from the literature. The region 47 − 50 eV seems to have been previously unexplored. Our results suggest that TICS, as a function of the photon energy, grows monotonously in the region 42− 50 eV. We also present fully resolved triple differential cross sections for selected photon energies. ∗ Corresponding author: [email protected] † On leave from the Institute of Spectroscopy, Russian Academy of Sciences
منابع مشابه
Criterion for Distinguishing Sequential from Nonsequential Contributions to the Double Ionization of Helium in Ultrashort Extreme-Ultraviolet Pulses.
We quantify sequential and nonsequential contributions in two-photon double ionization of helium atoms by intense ultrashort extreme-ultraviolet pulses with central photon energies ℏω_{ctr} near the sequential double-ionization threshold. If the spectrum of such pulses overlaps both the sequential (ℏω>54.4 eV) and nonsequential (ℏω<54.4 eV) double-ionization regimes, the sequential and nonseque...
متن کاملAngular distribution in two-photon double ionization of helium by intense attosecond soft X-ray pulses
Abstract We investigate two-photon double ionization of helium by intense (≈ 1015 W/cm2) ultrashort (≈ 300 as) soft X-ray pulses (E = 91.6 eV). The time-dependent two-electron Schrödinger equation is solved using a coupled channel method. We show that for ultrashort pulses the angular distribution of ejected electrons depends on the pulse duration and provides novel insights into the role of el...
متن کاملDirect two-photon double ionization of helium
The role of electron correlation, i.e. the electron-electron repulsion, in non-sequential two-photon double ionization of helium has been widely debated in literature, and the issue is not yet fully resolved. We present total cross sections for this process obtained within a one dimensional model of the helium atom. In our calculations the cross sections are obtained in two ways. Firstly, the t...
متن کاملAngular anisotropy parameters for sequential two-photon double ionization of helium
We evaluate photoelectron angular anisotropy parameters for the process of sequential two-photon double electron ionization of helium within the lowest-order time-independent perturbation theory. Our results indicate that for photoelectron energies outside the interval Eslow,Efast , where Eslow= −VHe+ and Efast= −VHe, there is a considerable deviation from the dipole angular distribution, thus ...
متن کاملPhotoionization dynamics in pure helium droplets.
The photoionization and photoelectron spectroscopy of pure He droplets were investigated at photon energies between 24.6 eV (the ionization energy of He) and 28.0 eV. Time-of-flight mass spectra and photoelectron images were obtained at a series of molecular beam source temperatures and pressures to assess the effect of droplet size on the photoionization dynamics. At source temperatures below ...
متن کامل