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

dc.contributor.advisorWalters, G. King
dc.creatorZhao, Xin-xin
dc.date.accessioned2009-06-04T00:37:34Z
dc.date.available2009-06-04T00:37:34Z
dc.date.issued1990
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.
dc.format.extent39 p.en_US
dc.format.mimetypeapplication/pdf
dc.identifier.callnoThesis Phys. 1990 Zhao
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>.
dc.identifier.urihttps://hdl.handle.net/1911/13486
dc.language.isoeng
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.
dc.subjectPhysics
dc.titleDynamics of conversion of atomic helium(triplet-2S) atoms to molecular helium(odd triplet-a-sigma-plus) molecules in ternary collisions (helium)
dc.typeThesis
dc.type.materialText
thesis.degree.departmentPhysics
thesis.degree.disciplineNatural Sciences
thesis.degree.grantorRice University
thesis.degree.levelMasters
thesis.degree.nameMaster of Arts
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