Dissociative excitation of a cesium atom in collisions of slow electrons with CsF molecules

The method of extended intersecting beams is used for studying inelastic collisions of electrons with cesium fluoride molecules. Forty-six cross-sections for dissociative excitation of the spectral lines of a cesium atom located in the spectral region 387–825 nm were used. The behavior of the sections in the spectral series of a cesium atom is investigated, which is reflected by a power law. The values of constants that are parameters in the power-law formula are determined. Moscow Power Engineering Institute, 14, Krasnokazarmennaya St., E-250, Moscow, 105835, Russia. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 1, pp. 20–25, January–February, 1997.     

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.     

Dissociative excitation cross sections of the lead atom in collisions between electrons and PbI2 molecules

Dissociative excitation of the lead atom in e-PbI₂ collisions has been studied experimentally. 27 excitation cross sections were measured for an energy of the exciting electrons equal to 100 eV. Nine optical excitation functions were recorded with variation of the electron energy in the range 0–100 eV. The most probable reaction channels for low electron energies are discussed, as well as the ratio of the dissociative excitation cross sections for the lead atom in e-PbI₂ and e-PbCl₂ collisions. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 6, pp. 701–706, November–December, 2006.     

Dissociative excitation of odd quintet levels of the iron atom by collisions of electrons with iron dichloride molecules

The dissociative excitation of odd quintet levels of the iron atom by collisions of slow electrons with iron dichloride molecules was studied using the method of extended crossing beams. Fifty-five dissociative excitation cross sections were measured at an excitation electron energy of 100 eV. Five optical excitation functions were recorded over an electron energy range from 0 to 100 eV. Some tendencies in the behavior of dissociative excitation cross sections were discussed.     

Dissociative excitation of doublet and octet levels of the manganese atom in collisions of electrons with manganese diiodide molecules

The dissociative excitation of doublet and octet levels of the manganese atom in collisions of slow electrons with manganese diiodide molecules is studied. At the exciting electron energy of 100 eV, the excitation cross sections for 28 and 12 transitions, respectively, from doublet and octet states of manganese atom are measured. In the exciting electron energy range of 0–100 eV, six optical excitation functions are recorded. The possible channels of the formation of excited manganese atoms at low electron energies are discussed.     

Dissociative excitation of even triplet and quintet levels of the iron atom in collisions of electrons with iron diiodide molecules

The method of extended crossing beams is used to study inelastic collisions of slow electrons with iron dichloride molecules. The dissociative excitation of even triplet and quintet levels of the iron atom at the incident electron energy of 100 eV is examined. The resulting dissociative excitation cross sections are compared to the cross sections of the excitation of FeI in electron-atom collisions.     

Dissociation-induced excitation of CsII in collisions of electrons with CsOH molecules

Dissociation-induced excitation of a singly charged cesium ion taking place as a result of collisions of electrons with CsOH molecules is investigated. Possible reaction channels in the low-energy region are discussed. It is established that sequential population plays an important role for 6p levels of Cs⁺. Moscow Power Engineering Institute, 14, Krasnokazarmennaya St., Moscow, 111250, Russia. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 65, No. 2, pp. 159–165, March–April, 1998.     

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.     

Dissociative attachment of electrons to excited molecules

The development and the first results from an experiment to carry out dissociative attachment to excited molecules are discussed. A brief summary of the relevance and status of such measurements are given. Apart from measuring the absolute cross sections from excited and state selected SO₂ molecule, we have been able to characterize the negative ion resonances using the excited state dissociative attachment. In addition, the state specificity of the electron attachment process has been used to derive information on the excited neutral state itself which has not been possible using optical spectroscopy. The applicability of this technique to other species are also discussed.     

Formation of excited cesium ions in collisions of electrons with cesium iodide molecules

The process of formation of excited Cs ions in simple collisions of electrons with CsI molecules was investigated by the method of extended intersecting beams. Excitation cross sections measured for CsII spectral lines were used in the calculation of cross sections for excitation of energy levels. The contribution of cascade transitions to the total cross section for excitation of an energy level was determined for certain levels. Possible ways of formation of Cs^+* at low energies of the electrons are discussed. Moscow Power Engineering Institute, 14, Krasnokazarmennaya Str., E-250, Moscow, 111250, Russia. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 3, pp. 316–322, May–June, 1999.     

Dissociative attachment of low-energy electrons to vibrationally excited hydrogen molecules

Dissociative electron attachment to hot hydrogen molecules is studied in the framework of nonlocal resonance model. The method based on the use of the Bateman approximation, well known in nuclear physics, is adapted for solving the Lippmann-Schwinger integral equation of the nonlocal resonance model and applied to the calculation of cross sections of inelastic resonant electron-molecule collisions. The proposed method is compared with the Schwinger-Lanczos algorithm used extensively for the treatment of these processes. It is shown that the Bateman approximation is very useful and efficient for treating the non-separable nonlocal potentials appearing in the integral kernels of the nonlocal resonance models. The calculated cross sections for the dissociative attachment of electrons to vibrationally excited hydrogen molecules are of importance for astrophysics. This paper is dedicated to Prof. J. Bičák on the occasion of his 60th birthday.     

Dissociative excitation of the cesium atom in e-CsCl collisions

The dissociative excitation of the cesium atom in collisions of slow electrons with cesium chloride molecules is studied by the method of extended crossed beams with detection of the optical signal from the crossing region. Forty-seven cross sections for the excitation of spectral lines of CsI in the spectral region 347–852 nm are measured at an electron energy of 100 eV, and 10 optical excitation functions (OEFs) are recorded. It is found that the dependence of the excitation cross sections on the principal quantum number of the upper level in the spectral series of Cs I corresponds to a power law. The characteristic values of the constants in the power law are determined for each of the investigated series. Zh. Tekh. Fiz. 69, 29–34 (January 1999)     

Formation of excited singly charged barium ions in collisions of slow electrons with barium dibromide molecules

The method of extended crossing beams is used to study inelastic collisions of slow electrons with barium dibromide molecules. The resulting optical emission spectrum contains only the spectral lines of the singly charged barium ion. At an exciting electron energy of 100 eV, the cross sections of dissociative excitation for nine spectral lines of BaII are measured; for all these lines, the optical excitation functions over an electron energy range of 0 to 100 eV are recorded. The possible channels of the dissociative excitation of BaII are discussed.     

Inelastic collisions of slow electrons with yttrium trichloride molecules

Inelastic collisions of electrons with YCl₃ molecules are investigated by the method of extended crossing beams. As in the case of LaCl₃ molecules, only the spectral lines of singly charged metal ions are found, with the lines of yttrium atoms and the spectral bands of yttrium monochloride being absent. The excitation cross sections of the energy levels of Y(II) and the contribution of the cascade population are calculated using the results obtained. Possible reaction channels upon dissociative excitation are discussed.     

The dissociative excitation of doublet and sextet manganese atom levels in collisions of electrons with manganese dibromide molecules

Inelastic collisions of electrons with manganese dibromide molecules were studied by the method of extended crossing beams. These collisions cause the formation of excited manganese atoms in doublet and sextet states. At an exciting electron energy of 100 eV, 52 dissociative excitation cross sections were measured. At electron energies 0–100 eV, three optical excitation functions were recorded. The ratio between excitation cross sections in electron-molecular and electron-atomic collisions is considered.     

The dissociative excitation of cobalt atom even sextet levels in collisions of electrons with CoCl2 molecules

The cross sections of dissociative excitation of 46 transitions from cobalt atom even sextet levels in collisions of electrons with CoCl₂ molecules were measured at an exciting electron energy of 100 eV. The dissociative and direct CoI excitation cross sections were compared. The results were used to calculate the total cross sections of dissociative excitation of CoI levels at an electron energy of 100 eV. Possible reaction channels at low electron energies are discussed.