相关论文: Depolarization of MgH Solar Lines by Collisions wi…
The semi-classical theory of collisional depolarization of spectral lines of neutral atoms by atomic hydrogen (Derouich et al. 2003a; Derouich et al. 2003b; Derouich et al. 2004 and references therein) is extended to spectral lines of…
[Abridged] Photoionization, whether by starlight or other sources, has difficulty in accounting for the observed spectra of the optical filaments that often surround central galaxies in large clusters. Our first paper examined whether…
Cross sections for the rotational (de)excitation of CO by ground state para- and ortho-H_2 are obtained using quantum scattering calculations for collision energies between 1 and 520 cm^{-1}. A new CO-H_2 potential energy surface is…
In this paper, using a standard quantum chemistry approach based on pseudopotentials for atomic core representation, Gaussian basis sets, and effective core polarization potentials, we investigate the electronic properties of the MgH$^+$…
Rate coefficients for inelastic Mg+H collisions are calculated for all transitions between the lowest seven levels and the ionic state (charge transfer). The rate coefficients are based on cross-sections from full quantum scattering…
We carry out calculations on $M$-changing collisions of NH ($^3\Sigma^-$) molecules in magnetically trappable states using a recently calculated potential energy surface. We show that elastic collision rates are much faster than inelastic…
This is a theoretical investigation on the formation of the linearly polarized line spectrum of ionized cerium in the sun. We calculate the scattering line polarization pattern emergent from a plane-parallel layer of Ce {\sc ii} atoms…
Ultracold collisions of polar OH molecules are considered in the presence of an electrostatic field. The field exerts a strong influence on both elastic and state-changing inelastic collision rate constants, leading to clear experimental…
We assess the partition function and ionization degree of magnetized hydrogen atoms at thermodynamic equilibrium for a wide range of field intensities, $B\approx 10^5$-$10^{12}$~G. Evaluations include fitting formulae for an arbitrary…
Radiative decay processes at cold and ultra cold temperatures for Sulfur atoms colliding with protons are investigated. The MOLPRO quantum chemistry suite of codes was used to obtain accurate potential energies and transition dipole…
We explore the total cross section of ground state polar molecules in an electric field at various energies, focusing on RbCs and RbK. An external electric field polarizes the molecules and induces strong dipolar interactions leading to…
Interstellar neutral atoms provide a remote diagnostic of plasma in the outer heliosheath and the very local interstellar medium via charge exchange collisions that convert ions into atoms and vice versa. So far, most studies of…
We present quantum dynamical calculations that describe the rotational excitation of H$_2$O due to collisions with H atoms. We used a recent, high accuracy potential energy surface, and solved the collisional dynamics with the…
Collisions of polar $^{1}\Sigma$ state molecules at ultralow energies are considered, within a model that accounts for long-range dipole-dipole interactions, plus rotation of the molecules. We predict a substantial suppression of…
The opacity due to photodissociation of 24MgH is investigated in the atmospheres of cool stars. The lowest two electronic transitions A 2Pi -- X 2Sigma+ and B' 2Sigma+ -- X 2 Sigma+ are considered where the cross sections for the latter…
Using two first-principles computer simulation techniques, path integral Monte-Carlo and density functional theory molecular dynamics, we derive the equation of state of magnesium in the regime of warm dense matter, with densities ranging…
Context. We present a theoretical review of the effect of impact polarization of a hydrogen H$\alpha$ line due to an expected proton beam bombardment in solar flares. Aims. Several observations indicate the presence of the linear…
The equation of state of liquid metallic hydrogen is solved numerically. Investigations are carried out at temperatures, which correspond both to the experimental conditions under which metallic hydrogen is produced on earth and the…
A theoretical method for the estimation of cross sections and rates for excitation and charge transfer processes in low-energy hydrogen atom collisions with neutral atoms, based on an asymptotic two-electron model of ionic-covalent…
We study hydrogen plasmas at magnetic fields B ~ 10^{12}-10^{13} Gauss, densities ~ 10^{-3}-10^3 g/cc and temperatures T ~ 10^{5.5}-10^{6.5} K, typical of photospheres of middle-aged cooling neutron stars. We construct an analytical free…