Translational and electronic energy dependence of S+ + H2(D2, HD) → SH+ (SD+) + H(D): spin-allowed and spin-forbidden pathways

Gregory F. Stowe; Richard H. Schultz; Charles A. Wight; P. B. Armentrout

doi:10.1016/0168-1176(90)85075-d

Translational and electronic energy dependence of S⁺ + H₂(D₂, HD) → SH⁺ (SD⁺) + H(D): spin-allowed and spin-forbidden pathways

Gregory F. Stowe, Richard H. Schultz, Charles A. Wight, P. B. Armentrout

University of Utah

Research output: Contribution to journal › Article › peer-review

39 Scopus citations

Abstract

Guided ion beam mass spectrometry is used to examine the kinetic energy dependence of the reaction of atomic sulfur ion with molecular hydrogen and its isotopic variants. By varying the conditions for S⁺ formation, it is possible to probe the cross-sections for ground and excited state ions. For excited states of S⁺, the reaction is efficient and behaves as predicted for an exothermic ion-molecule reaction. For the ⁴S ground state, the cross-section shows two distinct features: one which begins at the thermodynamic threshold for the reaction, and a larger one which occurs at higher energies. In reaction with HD, S⁺ (⁴S) forms equal amounts of SH⁺ and SD⁺ at low energies, but the higher energy pathway yields SD⁺ almost exclusively. These results are interpreted via new calculations of the potential energy surfaces for this system. We suggest that the low energy feature corresponds to a spin-forbidden surface transition, while the high energy feature is a spin-allowed process with a barrier that exceeds the reaction endothermicity by 0.3 eV.

Original language	English
Pages (from-to)	177-195
Number of pages	19
Journal	International Journal of Mass Spectrometry and Ion Processes
Volume	100
Issue number	C
DOIs	https://doi.org/10.1016/0168-1176(90)85075-d
State	Published - 31 Oct 1990
Externally published	Yes

Bibliographical note

Funding Information:
This work was supported by the National ScienceF oundation, Grant CHE-8917980T. he authorst hank ProfessorJ ack Simonsf or providinga ccess to the Utah-MESSkit programsa nd for computert ime on a Multiflow Trace 14/300m inisupercomputeirn his researchg roup. Helpful discussionsw ith ProfessorJ eff Nichols and memberso f the Simons researchg roup are gratefully acknowledged.M any of the calculationsw ere performed on a Sun MicrosystemsS PARCstation-1 computerw orkstationp urchasedw ith support from the Air Force Office of Scientific Research,G rant AFOSR-89-0103.

Funding

This work was supported by the National ScienceF oundation, Grant CHE-8917980T. he authorst hank ProfessorJ ack Simonsf or providinga ccess to the Utah-MESSkit programsa nd for computert ime on a Multiflow Trace 14/300m inisupercomputeirn his researchg roup. Helpful discussionsw ith ProfessorJ eff Nichols and memberso f the Simons researchg roup are gratefully acknowledged.M any of the calculationsw ere performed on a Sun MicrosystemsS PARCstation-1 computerw orkstationp urchasedw ith support from the Air Force Office of Scientific Research,G rant AFOSR-89-0103.

Funders	Funder number
National ScienceF oundation	CHE-8917980T
Air Force Office of Scientific Research	AFOSR-89-0103

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10.1016/0168-1176(90)85075-d

Cite this

@article{298b81be9d404531bac715af43f1dc30,

title = "Translational and electronic energy dependence of S+ + H2(D2, HD) → SH+ (SD+) + H(D): spin-allowed and spin-forbidden pathways",

abstract = "Guided ion beam mass spectrometry is used to examine the kinetic energy dependence of the reaction of atomic sulfur ion with molecular hydrogen and its isotopic variants. By varying the conditions for S+ formation, it is possible to probe the cross-sections for ground and excited state ions. For excited states of S+, the reaction is efficient and behaves as predicted for an exothermic ion-molecule reaction. For the 4S ground state, the cross-section shows two distinct features: one which begins at the thermodynamic threshold for the reaction, and a larger one which occurs at higher energies. In reaction with HD, S+ (4S) forms equal amounts of SH+ and SD+ at low energies, but the higher energy pathway yields SD+ almost exclusively. These results are interpreted via new calculations of the potential energy surfaces for this system. We suggest that the low energy feature corresponds to a spin-forbidden surface transition, while the high energy feature is a spin-allowed process with a barrier that exceeds the reaction endothermicity by 0.3 eV.",

author = "Stowe, {Gregory F.} and Schultz, {Richard H.} and Wight, {Charles A.} and Armentrout, {P. B.}",

note = "Funding Information: This work was supported by the National ScienceF oundation, Grant CHE-8917980T. he authorst hank ProfessorJ ack Simonsf or providinga ccess to the Utah-MESSkit programsa nd for computert ime on a Multiflow Trace 14/300m inisupercomputeirn his researchg roup. Helpful discussionsw ith ProfessorJ eff Nichols and memberso f the Simons researchg roup are gratefully acknowledged.M any of the calculationsw ere performed on a Sun MicrosystemsS PARCstation-1 computerw orkstationp urchasedw ith support from the Air Force Office of Scientific Research,G rant AFOSR-89-0103.",

year = "1990",

month = oct,

day = "31",

doi = "10.1016/0168-1176(90)85075-d",

language = "אנגלית",

volume = "100",

pages = "177--195",

journal = "International Journal of Mass Spectrometry and Ion Processes",

issn = "0168-1176",

publisher = "Elsevier",

number = "C",

}

Translational and electronic energy dependence of S⁺ + H₂(D₂, HD) → SH⁺ (SD⁺) + H(D): spin-allowed and spin-forbidden pathways. / Stowe, Gregory F.; Schultz, Richard H.; Wight, Charles A. et al.
In: International Journal of Mass Spectrometry and Ion Processes, Vol. 100, No. C, 31.10.1990, p. 177-195.

Research output: Contribution to journal › Article › peer-review

TY - JOUR

T1 - Translational and electronic energy dependence of S+ + H2(D2, HD) → SH+ (SD+) + H(D)

T2 - spin-allowed and spin-forbidden pathways

AU - Stowe, Gregory F.

AU - Schultz, Richard H.

AU - Wight, Charles A.

AU - Armentrout, P. B.

N1 - Funding Information: This work was supported by the National ScienceF oundation, Grant CHE-8917980T. he authorst hank ProfessorJ ack Simonsf or providinga ccess to the Utah-MESSkit programsa nd for computert ime on a Multiflow Trace 14/300m inisupercomputeirn his researchg roup. Helpful discussionsw ith ProfessorJ eff Nichols and memberso f the Simons researchg roup are gratefully acknowledged.M any of the calculationsw ere performed on a Sun MicrosystemsS PARCstation-1 computerw orkstationp urchasedw ith support from the Air Force Office of Scientific Research,G rant AFOSR-89-0103.

PY - 1990/10/31

Y1 - 1990/10/31

N2 - Guided ion beam mass spectrometry is used to examine the kinetic energy dependence of the reaction of atomic sulfur ion with molecular hydrogen and its isotopic variants. By varying the conditions for S+ formation, it is possible to probe the cross-sections for ground and excited state ions. For excited states of S+, the reaction is efficient and behaves as predicted for an exothermic ion-molecule reaction. For the 4S ground state, the cross-section shows two distinct features: one which begins at the thermodynamic threshold for the reaction, and a larger one which occurs at higher energies. In reaction with HD, S+ (4S) forms equal amounts of SH+ and SD+ at low energies, but the higher energy pathway yields SD+ almost exclusively. These results are interpreted via new calculations of the potential energy surfaces for this system. We suggest that the low energy feature corresponds to a spin-forbidden surface transition, while the high energy feature is a spin-allowed process with a barrier that exceeds the reaction endothermicity by 0.3 eV.

AB - Guided ion beam mass spectrometry is used to examine the kinetic energy dependence of the reaction of atomic sulfur ion with molecular hydrogen and its isotopic variants. By varying the conditions for S+ formation, it is possible to probe the cross-sections for ground and excited state ions. For excited states of S+, the reaction is efficient and behaves as predicted for an exothermic ion-molecule reaction. For the 4S ground state, the cross-section shows two distinct features: one which begins at the thermodynamic threshold for the reaction, and a larger one which occurs at higher energies. In reaction with HD, S+ (4S) forms equal amounts of SH+ and SD+ at low energies, but the higher energy pathway yields SD+ almost exclusively. These results are interpreted via new calculations of the potential energy surfaces for this system. We suggest that the low energy feature corresponds to a spin-forbidden surface transition, while the high energy feature is a spin-allowed process with a barrier that exceeds the reaction endothermicity by 0.3 eV.

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