1,721,070 research outputs found
Cross sections for the two-step radiative decay process X(v) → A(v′′) → X(v′) in e-LiH collisions
No full textAbstract: The cross sections for the two-step process, represented by the electron-impact vibro-electronic excitation X1Σ+(v) → A1Σ+(v′ ′) of the LiH molecule, followed by radiative decay back on the vibrational manifold of the ground state, A1Σ+(v′ ′) → X1Σ+(v′) , are calculated as a function of the incident electron energy from the threshold to 1000 eV. The final cross sections for the two-step process, which results in an overall vibrational excitation of the molecule, known also as E-v process, are provided for all the possible v, v′ transitions among the vibrational levels, including the continuum, of the electronic ground state. Graphic abstract: [Figure not available: see fulltext.
Electron-impact cross sections for processes involving vibrationally excited diatomic hydrogen molecules
No full textElectron-impact cross sections for processes involving vibrationally excited molecules of hydrogen and its isotopes are reviewed, briefly discussing their role in negative ion plasma sources
Dependence of Electron-Impact Excitation Cross-Sections on the Initial Vibrational Quantum Number in H-2 and D2 Molecules - X(1)Sigma-G+-]B(1)Sigma-U+ and X(1)Sigma-G+-]C(1)Pi-U Transitions
No full textElectron-impact excitation cross sections have been calculated using the impact-parameter method for X1SIGMA(g)+-->B1SIGMA(u)+ and X1SIGMA(g)+-->C1PI(u) transitions for both H-2 and D2 molecules as a function of incident energy and of vibrational quantum number v(i). The results show that the cross sections initially increase monotonically with increasing v(i) and follow the opposite trend for higher v(i) values
Total and dissociative electron-impact cross sections for X-1 Sigma(+)(g) -> B-1 Sigma(+)(u) and X-1 Sigma(+)(g) -> C-1 Pi(u) transitions of vibrationally excited tritium and deuterium-tritium molecules
No full textElectron-impact fetal and dissociative cross sections, calculated by using the impact-parameter method, for the X(1)Sigma (+)(g) --> B(1)Sigma (+)(u) and X(1)Sigma (+)(g) --> C(1)Pi (u) transitions of vibrationally excited T-2 and DT molecules, are presented. The mass and vibrational energy scalings of these cross sections are discussed
Equivalent Initial Conditions in the Study of Chemical Equilibrium: The Stoichiometric and Thermodynamic Points of View
No full textDissociative and energy transfer reactions involving vibrationally excited H2/D2 molecules
No full textAtomic and molecular processes involving vibrationally excited H-2/D2 molecules relevant to edge plasmas are reviewed. In particular, cross-sections for electron impact dissociation processes of vibrationally excited H-2(v) and D2(V) molecules (including dissociative attachment and dissociative ionization) as well as dissociation of H-2+(v) are presented and discussed. Also discussed are cross-sections for electron impact vibrational excitation of H-2(v) and D2(v) either by a resonant mechanism or by indirect excitation through electronic excited states radiatively cascading onto the ground state. For heavy particle molecular processes, the most important vibrational energy exchange processes due to the gas phase and to gas-surface collisions are discussed, namely the deactivation of H-2(V) and D2(v) by H-2/D2 and by atomic H/D species as well as in collisions with metallic surfaces
Scaling of electron-impact dissociative ionization cross sections of vibrationally excited H2 and D2 molecules
No full textA scaling law for electron-molecule collision cross sections for dissociative ionization of vibrationally excited H-2 and D-2 molecules is given as function of the collision energy and the vibrational quantum number
Towards a cross section database of excited atomic and molecular hydrogen
No full textElectron collision processes involving vibrationally excited diatomic hydrogen molecules and related cross sections are discussed. In particular, dissociative and non-dissociative electronic excitation and ionization, as well as radiative decay and dissociative attachment from H-2 molecules in their ground and excited (Rydberg) states, are considered. Finally, collision processes involving excited hydrogen atoms are also discussed due to their importance in affecting the transport properties of hydrogen plasmas
Electron-impact-induced allowed transitions between triplet states of H2
No full textElectron-impact-induced excitation and dissociation processes between the excited triplet states a (3)Sigma(g)(+)-->d (3)Pi(u), c (3)Pi(u)-->h (3)Sigma(g)(+), and c (3)Pi(u)-->g (3)Sigma(g)(+) of molecular hydrogen are studied by using the impact-parameter method. The cross sections for nu(i)-nu(f) resolved vibronic transitions between states have been calculated in the energy range from threshold to 100 eV; their maxima being located in the region of 5-10 eV. A special treatment was required for the transition to the h (3)Sigma(g)(+) state, whose adiabatic potential-energy curve possesses a barrier at the internuclear distance of about 5a(0), sustaining three quasi-bound vibrational states with widths of 5.3x10(-12), 1.5x10(-3), and 42.0 cm(-1), respectively. The quasistationary character of these vibrational states is taken into account when calculating the c (3)Pi(u)-->h (3)Sigma(g)(+) excitation and dissociation cross sections
Electron Impact Ionization of Metastable States of Diatomic Molecules
No full textThe Binary-Encounter Bethe approach was applied to the estimation of total ionization induced by electron impact in metastable states of diatomic molecules. The cross sections recently obtained for N2 and CO are reviewed and the new results for H2 are presented, discussing their reliability through the comparison with other theoretical methods
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