arXiv subjects

T. Meltzer

Publications and source records attributed to T. Meltzer.

4 recordsLinked to original sources

arXiv2024

Study of bound and resonant states of NS molecule in the R-matrix approach

The bound and resonance states along with corresponding autoionization widths for nitrogen sulphide (NS) molecule are determined using electron NS$^+$ cation scattering calculations. The calculations are performed for $^2{\Sigma}^+$, $^2{\Pi}$ and $^2\Delta$ total symmetries using the ab initio R-matrix method for both bound and continuum states. Calculations are performed on a grid of 106 points for internuclear separations between 1.32 and 3 $\AA$. The resonance states yield dissociative potential curves which, when considered together with their widths, provide input for models of different electron-cation collision processes including dissociative recombination, and rotational and vibrational excitation. Curves and couplings which will lead directly to dissociative recombination are identified.

astro-ph.IM↗

arXiv2020

Benchmark Calculations of Electron Impact Electronic Excitation of the Hydrogen Molecule

We present benchmark integrated and differential cross-sections for electron collisions with H$_2$ using two different theoretical approaches, namely, the R-matrix and molecular convergent close-coupling (MCCC). This is similar to comparative studies conducted on electron-atom collisions for H, He and Mg. Electron impact excitation to the $b \ ^3Σ_u^+$, $a \ ^3Σ_g^+$, $B \ ^1Σ_u^+$, $c \ ^3Π_u$, $EF \ ^1Σ_g^+$, $C \ ^1Π_u$, $e \ ^3Σ_u^+$, $h \ ^3Σ_g^+$, $B' \ ^1Σ_u^+$ and $d \ ^3Π_u$ excited electronic states are considered. Calculations are presented in both the fixed nuclei and adiabatic nuclei approximations, where the latter is shown only for the $b \ ^3Σ_u^+$ state. Good agreement is found for all transitions presented. Where available, we compare with existing experimental and recommended data.

physics.chem-ph↗

arXiv2017

Non-dipole recollision-gated double ionization and observable effects

Using a three-dimensional semiclassical model, we study double ionization for strongly-driven He fully accounting for magnetic field effects. For linearly and slightly elliptically polarized laser fields, we show that recollisions and the magnetic field combined act as a gate. This gate favors more transverse - with respect to the electric field - initial momenta of the tunneling electron that are opposite to the propagation direction of the laser field. In the absence of non-dipole effects, the transverse initial momentum is symmetric with respect to zero. We find that this asymmetry in the transverse initial momentum gives rise to an asymmetry in a double ionization observable. Finally, we show that this asymmetry in the transverse initial momentum of the tunneling electron accounts for a recently-reported unexpectedly large average sum of the electron momenta parallel to the propagation direction of the laser field.

physics.atom-ph↗

arXiv2016

Recollision as a probe of magnetic field effects in non-sequential double ionization

Fully accounting for non-dipole effects in the electron dynamics, double ionization is studied for He driven by a near-infrared laser field and for Xe driven by a mid-infrared laser field. Using a three-dimensional semiclassical model, the average sum of the electron momenta along the propagation direction of the laser field is computed. This sum is found to be an order of magnitude larger than twice the average electron momentum along the propagation direction of the laser field in single ionization. Moreover, the average sum of the electron momenta in double ionization is found to be maximum at intensities smaller than the intensities satisfying previously predicted criteria for the onset of magnetic field effects. It is shown that strong recollisions are the reason for this unexpectedly large value of the sum of the momenta along the direction of the magnetic component of the Lorentz force.

physics.atom-ph↗