Abstract
We present a global potential energy surface for the 1 A″ state of NH2 based on application of the reproducing kernel Hilbert space interpolation method to high quality ab initio (multireference configuration interaction) results. Extensive quasiclassical trajectory calculations are performed on this surface to study the N(2D) + H2/D2 reaction dynamics. Comparison is made with calculations on the lower level [first order configuration interaction (FOCI)] surface of Kobayashi, Takayanagi, Yokoyama, Sato, and Tsunashima (KTYST). We find a saddle point energy of 2.3 (1.9) kcal/mol for the perpendicular approach for the second order configuration interaction (SOCI) (SOCI with Davidson correction) surfaces, and a collinear stationary point energy of 5.5 (4.6) kcal/mol. The ordering of these stationary points is reversed compared to the corresponding FOCI results, and the only true reaction path on our surface is perpendicular. The primary reaction mechanism is determined to be C2v insertion to produce short lived (100-300 fs) NH2 intermediates. Angular distributions are found to be primarily forward-backward symmetric, with a slight bias towards backward scattering at low energies. Decay of the NH2's occurs before energy is fully randomized, so the product vibrational distributions are a little hotter than statistical - with vibrational population ratios NH(v″=1)/NH(v″=0) = 0.8 and ND(v″=1)/ND(v″ = 0) = 0.9 (near threshold). These ratios, and other aspects of the vibrational product distributions are in excellent agreement with recent laser induced fluorescence studies.
| Original language | English |
|---|---|
| Pages (from-to) | 9091-9100 |
| Number of pages | 10 |
| Journal | Journal of Chemical Physics |
| Volume | 110 |
| Issue number | 18 |
| Publication status | Published - May 8 1999 |
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ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry
Cite this
Potential energy surface and quasiclassical trajectory studies of the N(2D) + H2 reaction. / Pederson, Lisa A.; Schatz, George C.
In: Journal of Chemical Physics, Vol. 110, No. 18, 08.05.1999, p. 9091-9100.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Potential energy surface and quasiclassical trajectory studies of the N(2D) + H2 reaction
AU - Pederson, Lisa A.
AU - Schatz, George C
PY - 1999/5/8
Y1 - 1999/5/8
N2 - We present a global potential energy surface for the 1 A″ state of NH2 based on application of the reproducing kernel Hilbert space interpolation method to high quality ab initio (multireference configuration interaction) results. Extensive quasiclassical trajectory calculations are performed on this surface to study the N(2D) + H2/D2 reaction dynamics. Comparison is made with calculations on the lower level [first order configuration interaction (FOCI)] surface of Kobayashi, Takayanagi, Yokoyama, Sato, and Tsunashima (KTYST). We find a saddle point energy of 2.3 (1.9) kcal/mol for the perpendicular approach for the second order configuration interaction (SOCI) (SOCI with Davidson correction) surfaces, and a collinear stationary point energy of 5.5 (4.6) kcal/mol. The ordering of these stationary points is reversed compared to the corresponding FOCI results, and the only true reaction path on our surface is perpendicular. The primary reaction mechanism is determined to be C2v insertion to produce short lived (100-300 fs) NH2 intermediates. Angular distributions are found to be primarily forward-backward symmetric, with a slight bias towards backward scattering at low energies. Decay of the NH2's occurs before energy is fully randomized, so the product vibrational distributions are a little hotter than statistical - with vibrational population ratios NH(v″=1)/NH(v″=0) = 0.8 and ND(v″=1)/ND(v″ = 0) = 0.9 (near threshold). These ratios, and other aspects of the vibrational product distributions are in excellent agreement with recent laser induced fluorescence studies.
AB - We present a global potential energy surface for the 1 A″ state of NH2 based on application of the reproducing kernel Hilbert space interpolation method to high quality ab initio (multireference configuration interaction) results. Extensive quasiclassical trajectory calculations are performed on this surface to study the N(2D) + H2/D2 reaction dynamics. Comparison is made with calculations on the lower level [first order configuration interaction (FOCI)] surface of Kobayashi, Takayanagi, Yokoyama, Sato, and Tsunashima (KTYST). We find a saddle point energy of 2.3 (1.9) kcal/mol for the perpendicular approach for the second order configuration interaction (SOCI) (SOCI with Davidson correction) surfaces, and a collinear stationary point energy of 5.5 (4.6) kcal/mol. The ordering of these stationary points is reversed compared to the corresponding FOCI results, and the only true reaction path on our surface is perpendicular. The primary reaction mechanism is determined to be C2v insertion to produce short lived (100-300 fs) NH2 intermediates. Angular distributions are found to be primarily forward-backward symmetric, with a slight bias towards backward scattering at low energies. Decay of the NH2's occurs before energy is fully randomized, so the product vibrational distributions are a little hotter than statistical - with vibrational population ratios NH(v″=1)/NH(v″=0) = 0.8 and ND(v″=1)/ND(v″ = 0) = 0.9 (near threshold). These ratios, and other aspects of the vibrational product distributions are in excellent agreement with recent laser induced fluorescence studies.
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M3 - Article
VL - 110
SP - 9091
EP - 9100
JO - Journal of Chemical Physics
JF - Journal of Chemical Physics
SN - 0021-9606
IS - 18
ER -