INELASTIC SCATTERING FROM A DIATOMIC MOLECULE: ROTATIONAL EXCITATION UPON COLLISION BETWEEN He AND H$sub 2$ AND H$sub 2$ AND H$sub 2$
The formalism developed by Arthurs and Dalgarno was used in the distorted wave approximation to calculate the inelastic scattering cross section for rotational excitation from the j = 0 to the j = 2 rotational state in collisions between a helium atom and a hydrogen molecule or two hydrogen molecules. All necessary computations were done with a digital computer, thus, allowing the Arthurs-Dalgarno formalism to be applied with no added approximations. The interaction energy between He and H/sub 2/ obtained previously was used for the He-- H/sub 2/ calculation while the interaction energy given by Takayanagi was used for the H/sub 2/-- H/sub 2/ problem. Values for the total inelastic cross sections are given as well as graphs for the He-H/ sub 2/ differential scattering cross section. Incident kinetic energies up to oniy 0.25 ev in the center-of-mass system were considered; for these low energies, vibrational or electronic excitation is impossible so that change in rotational quantum number is the only inelastic process possible. The results obtained for the H/sub 2/-H/sub 2/ cross section do not agree with the rate of deexcitation from the j = 2 rotational level in H/sub 2/ gas as measured by dispersion experiments with ultrasonic waves. The disagreement may be due to an incorrect H/sub 2/-H/sub 2/ interaction potential or failure to consider all important de-excitation mechanisms. (auth)
- Research Organization:
- Massachusetts Inst. of Tech., Cambridge
- NSA Number:
- NSA-17-025941
- OSTI ID:
- 4706606
- Journal Information:
- Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D, Journal Name: Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D Vol. Vol: 131; ISSN PHRVA
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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