Elastic processes involving vibrationally excited molecules in cold hydrogen plasmas

We describe here a comprehensive quantum mechanical study of elastic scattering of protons by vibrationally excited hydrogen molecules and of hydrogen atoms by vibrationally excited hydrogen molecular ions, in the range of collision energies from a fraction of an eV to 6 eV. The problem was solved within a treatment considering all inelastic processes between the vibrational states, including excitation, charge transfer and dissociation. This was realized by expanding the problem in vibrational bases of H2 and H2+ which, in addition to all bound states, contained a large number of discretized vibrational continuum states, and solving the resulting set of coupled channel equations. The sudden approximation was applied with regard to rotations of the target molecule, and particular attention has been paid to convergence of the elastic cross sections with the number of partial waves of the projectile. Important plasma transport related moments of the elastic scattering cross section, the momentum transfer and viscosity cross sections, are also reported here and compared with inelastic cross sections for various vibrationally excited states.

[1]  O. Iwamoto,et al.  Cross sections for the reaction H+ + H2 (v = 0-14) →H + H2+ at low collision energies , 2000 .

[2]  E. W. McDaniel,et al.  Atomic collisions : heavy particle projectiles , 1993 .

[3]  R. Janev.  Atomic and Molecular Processes in SOL/Divertor Plasmas , 1998 .

[4]  J. Tully,et al.  Effects of surface crossing in chemical reactions - The H3 system , 1971 .

[5]  B. R. Johnson,et al.  The multichannel log-derivative method for scattering calculations , 1973 .

[6]  M. Baer,et al.  A three-dimensional quantum mechanical study of vibrationally resolved charge transfer processes in H++H2 at Ecm=20 eV , 1989 .

[7]  P. Krstic,et al.  CONSISTENT DEFINITIONS FOR, AND RELATIONSHIPS AMONG, CROSS SECTIONS FOR ELASTIC SCATTERING OF HYDROGEN IONS, ATOMS, AND MOLECULES , 1999 .

[8]  D. Schultz,et al.  ELASTIC AND VIBRATIONALLY INELASTIC SLOW COLLISIONS : H + H2, H+ + H2 , 1999 .

[9]  Hiroki Nakamura,et al.  A three‐dimensional, quantum mechanical study of exchange and charge transfer processes in the (Ar+H2)+ system , 1987 .

[10]  P. Krstic,et al.  Elastic scattering and charge transfer in slow collisions: isotopes of H and H+ colliding with isotopes of H and with He , 1999 .

[11]  R. T. Pack.  Space‐fixed vs body‐fixed axes in atom‐diatomic molecule scattering. Sudden approximations , 1974 .

[12]  P. Krstic,et al.  Inelastic Processes from Vibrationally Excited States in Slow H , 2002 .

[13]  F. O. Ellison.  A Method of Diatomics in Molecules. I. General Theory and Application to H2O , 1963 .

[14]  D. Secrest.  Theory of angular momentum decoupling approximations for rotational transitions in scattering , 1975 .

[15]  L. M. Delves,et al.  TERTIARY AND GENERAL-ORDER COLLISIONS. PART II , 1960 .

[16]  M. Baer,et al.  A comparison between theoretical and experimental state‐to‐state charge transfer cross sections for H++H2 at 20 eV: Evidence for quantum effects , 1988 .