Dynamics of conversion of atomic helium(triplet-2S) atoms to molecular helium(odd triplet-a-sigma-plus) molecules in ternary collisions (helium)

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dc.contributor.advisorWalters, G. Kingen_US
dc.creatorZhao, Xin-xinen_US
dc.date.accessioned2009-06-04T00:37:34Zen_US
dc.date.available2009-06-04T00:37:34Zen_US
dc.date.issued1990en_US
dc.description.abstractThe temperature dependence of conversion of He(2$\sp3$S$\sb1$) metastable atoms to He$\sb2$(a$\sp3\Sigma\sp+\sb{\rm u}$) metastable molecules in the three-body reaction$$\rm He(2\sp3S\sb1)+2He(1\sp1S\sb0) \to He\sb2(a\sp3\Sigma\sp+\sb{u})+He(1\sp1S\sb0)$$has been investigated over the temperature range 65K-700K. This reaction is thermally activated as a consequence of a long range repulsive barrier in the He(2$\sp3$S$\sb1)$-He(1$\sp1$S$\sb0$) interaction potential. The data reveal that there are two reaction channels with distinctly different activation energies. The temperature dependence of the measured rate coefficient $\delta$(T) is accurately described by$$\rm \delta(T) = \lbrack 87.4\ T\ exp({-}750/T){+}4.1T\ exp({-}200/T)\rbrack \times 10\sp{-37}\ cm\sp{-6}sec\sp{-1}.$$The first activation energy, 750 $\pm$ 70K(63 $\pm$ 6meV), is equal to the known He(2$\sp3$S$\sb1)$-He(1$\sp1$S$\sb0$) repulsive barrier height. The second activation energy is 17 $\pm$ 2 meV.en_US
dc.format.extent39 p.en_US
dc.format.mimetypeapplication/pdfen_US
dc.identifier.callnoThesis Phys. 1990 Zhaoen_US
dc.identifier.citationZhao, Xin-xin. "Dynamics of conversion of atomic helium(triplet-2S) atoms to molecular helium(odd triplet-a-sigma-plus) molecules in ternary collisions (helium)." (1990) Master’s Thesis, Rice University. <a href="https://hdl.handle.net/1911/13486">https://hdl.handle.net/1911/13486</a>.en_US
dc.identifier.urihttps://hdl.handle.net/1911/13486en_US
dc.language.isoengen_US
dc.rightsCopyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder.en_US
dc.subjectPhysicsen_US
dc.titleDynamics of conversion of atomic helium(triplet-2S) atoms to molecular helium(odd triplet-a-sigma-plus) molecules in ternary collisions (helium)en_US
dc.typeThesisen_US
dc.type.materialTexten_US
thesis.degree.departmentPhysicsen_US
thesis.degree.disciplineNatural Sciencesen_US
thesis.degree.grantorRice Universityen_US
thesis.degree.levelMastersen_US
thesis.degree.nameMaster of Artsen_US
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