Auger decay and the direct double ionization probability of a 2p inner-shell hole in a singly charged Ar+ ion

We have performed multi-component full-configuration interaction calculations to investigate the nature of chemical bonding of [LiH;e⁺] at the small and large internuclear distance. We discuss the importance of geometrical changes in positronic compounds induced by a positron attachment in terms of the virial theorem, with a comparison of the adiabatic- and vertical-positron affinity (PA). The systematic improvement of the PA values achieved by optimisation of (i) the molecular geometry and (ii) the positronic basis centre is also discussed. The stable dissociation channel of [LiH;e⁺] is compared with the ionic- and neutral-dissociation channels of its parent molecule LiH through the analysis of the potential energy curve and the electronic and positronic densities. The vertical PA as a function of is also presented, which is the difference between the potential energy curve of the parent molecule (LiH → Li + H) and its positronic compound ([LiH; e⁺] → Li + [H; e⁺]). Unlike the preceding study of [M. Mella et al., J. Chem. Phys. 113, 6154 (2000)], it took more than bohr to converge the vertical PA due to the long-range ionic bonding interaction.     

Excitation of a singly charged barium ion in electron-atom collisions

Results of the experimental study of excitation of transitions of singly charged barium atoms in collisions of low-energy monokinetic electrons with barium atoms are presented. Regularities of the behavior of cross sections for excitation in spectral series of BaII are found. The results are compared with other authors’ results.     

Dissociative excitation of the singly charged manganese ion in collisions of electrons with manganese diiodide molecules

The dissociative excitation of the singly charged manganese ion in collisions of electrons with MnI₂ molecules is experimentally studied. At exciting electron energy of 100 eV, 16 dissociative excitation cross sections were measured. The studied transitions occur within the quintet and septet term systems in the absence of intercombination transitions. The measured values of the cross sections are compared to similar values obtained previously in studies of e–MnCl₂ and e–MnBr₂ collisions.     

Excitation of a singly charged indium ion by electron impact

Inelastic collisions of slow electrons with indium atoms resulting in the production of excited singly charged indium ions are experimentally studied. Excitation cross sections of 123 InII spectral lines are measured at the excitation electron energy of 30 eV. Nine optical excitation functions are recorded. The dependence of the excitation cross sections on the principal quantum number of the upper level is examined for 12 InII spectral series.     

Excitation of singlet levels of a singly charged scandium ion in e-Sc collisions

The excitation of singlet levels of the singly charged scandium ion is experimentally studied in collisions of slow electrons with scandium atoms. At the exciting electron energy of 30 eV, 59 excitation cross sections are measured. In the electron energy range of 0–200 eV, seven optical excitation functions are recorded. On the basis of these data the total excitation cross sections are calculated for 11 even and 9 odd levels of Sc II, as well as the contribution of cascade population to 8 even and 7 odd levels.     

The dissociative excitation of singlet levels of the singly charged lanthanum ion in collisions of electrons with lanthanum bromide molecules

The method of extended crossing beams was used to study inelastic collisions of slow electrons with LaBr₃ molecules. Dissociative excitation caused the appearance of spectral lines of the singly charged lanthanum ion. 38 dissociative excitation cross sections of LaII spectral lines (upper singlet levels) were studied at a 100 eV exciting electron energy. Three optical excitation functions were recorded over the electron energy range 0–100 eV. The cross sections obtained are compared with the data on dissociative excitation cross sections of the LaCl₃ molecule.     

Dissociative excitation of even levels of the singly charged yttrium ion in collisions of slow electrons with yttrium tribromide molecules

The method of extended crossing beams in conjunction with optical spectroscopy is used to study the dissociative excitation of even levels of YII in e-YBr₃ collisions. At the exciting electron energy of 100 eV, 38 dissociative excitation cross sections are measured. Comparison of these cross sections with the cross sections for direct excitation in e-Y collisions shows that, for all the investigated even levels of YII, dissociative excitation is more efficient than direct one.     

Excitation of singly charged germanium ion from the ground state of GeI

Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 53, No. 2, pp. 197–201, August, 1990.     

Variational method for inner-shell excitation in heavy-ion collisions

In the framework of the monopole model we study a perturbation method for inner-shell excitation which covers the whole projectile velocity region. This is achieved by introducing a velocity-dependent variational parameter and minimizing the time-dependent perturbation. We apply the method to theK-excitation of nonrelativistic systems.     

On the band structure of silver and platinum from angle-resolved photoelectron spectroscopy (ARUPS) measurements

The general problems of an accurate a priori determination of electronic band structures are discussed. Data for the L line in Ag and Pt will be discussed as a case in point. Various methods have been employed to determine the electron wavevectorK of the direct transitions to the bands accessible to photon energieshv=16.9 eV and 21.2 eV: the disappearance and appearance angle method, the symmetry method, the triangulation method and the gap emission method. It is found that the experimentalE(K) points agree well within ±0.5 eV with a recently ab initio calculated conduction band structure. We further have measured Ag(111) normal emission AREDC's in the photon energy range 11 eVhv25 eV and have found that the intensity behaviour with photon energy of the direct transitions compares well with calculated bulk momentum matrix elements for Ag along . A summary of the experimentalE(K) data for both the conduction and valence bands in Ag is given and compared with a recent local density calculation. Similar investigations for Pt are presented.Dedicated to B. Mühlschlegel on the occasion of his 60th birthday     

Photoinduced reconfiguration cycle in a molecular adsorbate layer studied by femtosecond inner-shell photoelectron spectroscopy

A time-resolved study of core-level chemical shifts in a monolayer of aromatic molecules reveals complex photoinduced reaction dynamics. The combination of electron spectroscopy for chemical analysis and ultrashort pulse excitation in the extreme ultraviolet allows performing time-correlated 4d-core-level spectroscopy of iodine atoms that probe the local chemical environment in the adsorbate molecule. The selectivity of the method unveils metastable molecular configurations that appear about 50 ps after the excitation and are efficiently quenched back to the ground state.     

Influence of two-pair continuum correlations following resonant excitation of excitons

The memory structure induced by coherent transitions to the exciton-exciton scattering continuum is shown to have significant influence on spectrally resolved four-wave-mixing signals even under selective excitation of 1s excitons. Comparisons between experiments and calculations that account nonperturbatively for these quantum kinetic Coulomb correlations demonstrate large compensations between mean-field contributions and transitions to the two-pair continuum. Experiments with different polarizations of the laser pulses show that two-pair continuum correlations are responsible for delay-time dependent shifts of the excitonic emission as well as for substantial deformations of the line shape.