Cross sections for the vibrational excitation of the H sub 2 X sup 1. Sigma. sup + sub g ( v ) levels generated by electron collisional excitation of the higher singlet states

Journal Article · Tue Oct 01 04:00:00 EDT 1991 · Journal of Applied Physics; (United States)

DOI:https://doi.org/10.1063/1.349284· OSTI ID:5247169

Hiskes, J R ^[1]

---

1. Lawrence Livermore National Laboratory, University of California, Livermore, California (USA)

The excitation cross sections, {sigma}({ital v},{ital v}{double prime}), for an H{sub 2} molecule initially in any one of the 15 vibrational levels, {ital v} belonging to the ground electronic state and excited to a final vibrational level, {ital v}{double prime} are evaluated for direct excitations via all members of the excited electronic singlet spectrum. Account is taken of predissociation, autoionization, and radiative decay of the excited electronic spectrum that leads to a final population distribution for the ground electronic state, {ital X} {sup 1}{Sigma}{sup +}{sub {ital g}}({ital v}{double prime}). For {ital v}=0, account is taken explicitly of transitions via the {ital B}, {ital C}, {ital B}{prime}, and {ital D} electronic states in evaluating the cross sections. The additional contribution of excitations via all Rydberg states lying above the {ital D} state enhances these cross sections by approximately 10%. For {ital v}{gt}0, cross sections are evaluated taking explicit account of transitions through the {ital B} and {ital C} states; higher singlet excitations enhance these values by 25%. The choice of the reference total cross sections remains a subjective one, causing the values calculated here to have a possible uncertainty of {sup +20%}{sub {minus}30%}. For excitations occurring within a hydrogen discharge, collisional excitation-ionization events among the intermediate singlet states will effectively quench the {ital v}, {ital v}{double prime} excitation process for discharge densities in excess of the range 10{sup 15}--10{sup 16} electrons/cm{sup {minus}3}.

• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 5247169
• Journal Information: Journal of Applied Physics; (United States), Journal Name: Journal of Applied Physics; (United States) Vol. 70:7; ISSN 0021-8979; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

08 HYDROGEN
080000 -- Hydrogen
640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
COLLISIONS
CROSS SECTIONS
DATA
ELECTRON COLLISIONS
ELECTRON-MOLECULE COLLISIONS
ELEMENTS
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
EXCITATION
EXCITED STATES
HYDROGEN
INFORMATION
MOLECULE COLLISIONS
NONMETALS
NUMERICAL DATA
THEORETICAL DATA
VIBRATIONAL STATES