Comparison of the harmonic and morse oscillator models in He + I/sub 2/ collisions using the vibrational/rotational infinite-order sudden approximation

Journal Article · Thu Mar 12 04:00:00 EST 1987 · J. Phys. Chem.; (United States)

DOI:https://doi.org/10.1021/j100290a028· OSTI ID:6772955

Eggert, S; Tellez, S; Pfeffer, G A

The recently developed vibrational/rotational infinite-order sudden approximation (VRIOSA) has been used to investigate the effect of the oscillator model for the diatomic molecule upon He and I/sub 2/ collisions at energies ranging from 0.044 to 0.5 eV. The two models used were the harmonic and Morse oscillators; integral and differential cross sections for vibrational transitions from 0 ..-->.. 0, 1, 2, or 3 and for rotational transitions from 0 ..-->.. 0, 10, 20, 30, 40, 50, and 60 have been calculated with both models. The results of these two oscillators are compared to each other, to vibrational close-coupled infinite-order sudden approximation (VCC-IOSA) results obtained with the Morse oscillator, and to experimental results. The present work extends the previous oscillator comparisons by employing a three-dimensional quantum formalism, by considering a large array of rotational and vibrational transitions, by including the differential cross sections and an experimentally obtainable cross section, and by focusing on a non-hydrogen-containing diatomic molecule. The VRIOSA is also advantageous for these studies under certain conditions. In general, the two oscillator models agree well when the vibrational quantum number change is small and when the energy is high. In addition, the more highly averaged the cross sections, the more closely the models agree with one another. However, for some transitions and values of the scattering angle, there are differences of orders of magnitude in the differential cross sections. In this study, the effect of a change in the oscillator wave function upon the cross sections was larger than the effect of a change in the oscillator energy levels.

• Research Organization: Univ. of Nebraska, Omaha
• OSTI ID: 6772955
• Journal Information: J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 91:6; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ATOM COLLISIONS
ATOM-MOLECULE COLLISIONS
CHEMICAL REACTIONS
COLLISIONS
CROSS SECTIONS
DATA
DIFFERENTIAL CROSS SECTIONS
ELEMENTS
ENERGY LEVELS
EXCITED STATES
FLUIDS
FUNCTIONS
GASES
HALOGENS
HARMONIC OSCILLATOR MODELS
HELIUM
INFORMATION
IODINE
MATHEMATICAL MODELS
MOLECULE COLLISIONS
MORSE POTENTIAL
NONMETALS
NUMERICAL DATA
POTENTIALS
RARE GASES
SUDDEN APPROXIMATION
THEORETICAL DATA
VIBRATIONAL STATES
WAVE FUNCTIONS