Potential energy surface of the à state of NH2 and the role of excited states in the N(2D) + H2 reaction

Lisa A. Pederson, George C Schatz, Timothy Hollebeek, Tak San Ho, Herschel Rabitz, Lawrence B. Harding

Research output: Contribution to journalArticle

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Abstract

We present a global potential energy surface for the à state of NH2 (12A') based on application of the reproducing kernel Hilbert space (RKHS) interpolation method to high-quality ab initio (multireference configuration-interaction) results. This surface correlates adiabatically to the a1 Δ state of NH, with a reaction endoergicity of about 8 kcal/mol, but it can also lead to formation of ground-state NH (exoergic by 29 kcal/ mol) via nonadiabatic (Renner-Teller) interactions for linear HNH geometries that lie near the bottom of a 94 kcal/mol deep well that is accessible from N(2D) + H2 by insertion over a 3.4 kcal/mol barrier. This insertion barrier is about 1 kcal/mol higher in energy than the corresponding insertion barrier associated with the ground state of NH2(12A"). As a result, the à state contributes measurably to both the thermal rate constant for N(2D) + H2 and the rate for NH(a1Δ) production. Extensive quasiclassical trajectory calculations are performed on the RKHS surface to study the N(2D) + H2 reaction dynamics, with the nonadiabatic rate constant estimated using a capture model. We find that the cross section for ground-state NH production is comparable to that obtained on the ground-state 1A" surface, except for a 1 kcal/mol shift upward in the effective threshold due to the different barrier height. The cross section for NH(a1Δ) production has a higher threshold energy and is about 15% of the ground-state cross section at energies well above threshold.

Original languageEnglish
Pages (from-to)2301-2307
Number of pages7
JournalJournal of Physical Chemistry A
Volume104
Issue number11
Publication statusPublished - Mar 23 2000

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Potential energy surfaces
Excited states
Ground state
potential energy
ground state
insertion
excitation
Hilbert spaces
Hilbert space
thresholds
Rate constants
cross sections
configuration interaction
interpolation
energy
Interpolation
Trajectories
trajectories
Geometry
shift

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

Cite this

Pederson, L. A., Schatz, G. C., Hollebeek, T., Ho, T. S., Rabitz, H., & Harding, L. B. (2000). Potential energy surface of the à state of NH2 and the role of excited states in the N(2D) + H2 reaction. Journal of Physical Chemistry A, 104(11), 2301-2307.

Potential energy surface of the à state of NH2 and the role of excited states in the N(2D) + H2 reaction. / Pederson, Lisa A.; Schatz, George C; Hollebeek, Timothy; Ho, Tak San; Rabitz, Herschel; Harding, Lawrence B.

In: Journal of Physical Chemistry A, Vol. 104, No. 11, 23.03.2000, p. 2301-2307.

Research output: Contribution to journalArticle

Pederson, LA, Schatz, GC, Hollebeek, T, Ho, TS, Rabitz, H & Harding, LB 2000, 'Potential energy surface of the à state of NH2 and the role of excited states in the N(2D) + H2 reaction', Journal of Physical Chemistry A, vol. 104, no. 11, pp. 2301-2307.
Pederson, Lisa A. ; Schatz, George C ; Hollebeek, Timothy ; Ho, Tak San ; Rabitz, Herschel ; Harding, Lawrence B. / Potential energy surface of the à state of NH2 and the role of excited states in the N(2D) + H2 reaction. In: Journal of Physical Chemistry A. 2000 ; Vol. 104, No. 11. pp. 2301-2307.
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