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A new potential energy surface for the H2S system and dynamics study on the S((1)D) + H2(X(1)Σg(+)) reaction.

Yuan J, He D, Chen M - Sci Rep (2015)

Bottom Line: The calculated integral cross sections decrease with increasing collision energy and remain fairly constant within the high collision energy range.Both forward and backward scatterings can be observed as expected for a barrierless reaction with a deep well on the PES.The calculated integral cross sections and differential cross sections are in good agreement with the experimental results.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Materials Modification by Laser, Electron, and Ion Beams (Ministry of Education), School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024, PR China.

ABSTRACT
We constructed a new global potential energy surface (PES) for the electronic ground state ((1)A') of H2S based on 21,300 accurate ab initio energy points over a large configuration space. The ab initio energies are obtained from multireference configuration interaction calculations with a Davidson correction using basis sets of quadruple zeta quality. The neural network method is applied to fit the PES, and the root mean square error of fitting is small (1.68 meV). Time-dependent wave packet studies for the S((1)D) + H2(X(1)Σg(+)) → H((2)S) + SH(X(2)Π) reaction on the new PES are conducted to study the reaction dynamics. The calculated integral cross sections decrease with increasing collision energy and remain fairly constant within the high collision energy range. Both forward and backward scatterings can be observed as expected for a barrierless reaction with a deep well on the PES. The calculated integral cross sections and differential cross sections are in good agreement with the experimental results.

No MeSH data available.


The total DCSs of the S(1D) + H2(X1Σg+) → H(2S) + SH(X2Π) reaction calculated by the TDWP method at two collision energies ((a) 2.24 kcal/mol and (b) 3.96 kcal/mol), compared with the experimental data 5 and previous theoretical results1620.Because the theoretical results20 obtained from DMBE/CBS and DMBE/SEC PESs are relative, previous theoretical results have been scaled separately to make the value at 90º equal to our result.
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f7: The total DCSs of the S(1D) + H2(X1Σg+) → H(2S) + SH(X2Π) reaction calculated by the TDWP method at two collision energies ((a) 2.24 kcal/mol and (b) 3.96 kcal/mol), compared with the experimental data 5 and previous theoretical results1620.Because the theoretical results20 obtained from DMBE/CBS and DMBE/SEC PESs are relative, previous theoretical results have been scaled separately to make the value at 90º equal to our result.

Mentions: To further verify the new PES, we calculated the total DCSs of the S(1D) + H2(X1Σg+) → H(2S) + SH(X2Π) reaction according to the TDWP method at the two collision energies (2.24 kcal/mol and 3.96 kcal/mol) displayed in Fig. 7. The experimental results5 and several theoretical results1620 are also shown in the figure. Because the theoretical results obtained from DMBE/CBS and DMBE/SEC PESs are relative in the paper of Hankel and co-workers20, the previous theoretical results have been scaled separately to make the value at 90° equal to our result for comparison. For the experimental results and all of the theoretical results, both forward and backward scattering can be observed in the reaction as expected for a reaction with a deep well and no barrier. The DCSs are not strictly backward-forward symmetric. At the collision energy of 2.24 kcal/mol, a slight forward preference is found in the experimental results, and the DCSs obtained from the new PES reproduce this feature well. However, other previous theoretical results, particularly the DCSs16 obtained from Ho PES, show an opposite preference. For the collision energy of 3.96 kcal/mol, the forward preference in the experiment results is more significant, and our results match the preference well. The DCSs obtained from DMBE/CBS and DMBE/SEC PESs show a significant backward preference, contrary to the experimental results.


A new potential energy surface for the H2S system and dynamics study on the S((1)D) + H2(X(1)Σg(+)) reaction.

Yuan J, He D, Chen M - Sci Rep (2015)

The total DCSs of the S(1D) + H2(X1Σg+) → H(2S) + SH(X2Π) reaction calculated by the TDWP method at two collision energies ((a) 2.24 kcal/mol and (b) 3.96 kcal/mol), compared with the experimental data 5 and previous theoretical results1620.Because the theoretical results20 obtained from DMBE/CBS and DMBE/SEC PESs are relative, previous theoretical results have been scaled separately to make the value at 90º equal to our result.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4592959&req=5

f7: The total DCSs of the S(1D) + H2(X1Σg+) → H(2S) + SH(X2Π) reaction calculated by the TDWP method at two collision energies ((a) 2.24 kcal/mol and (b) 3.96 kcal/mol), compared with the experimental data 5 and previous theoretical results1620.Because the theoretical results20 obtained from DMBE/CBS and DMBE/SEC PESs are relative, previous theoretical results have been scaled separately to make the value at 90º equal to our result.
Mentions: To further verify the new PES, we calculated the total DCSs of the S(1D) + H2(X1Σg+) → H(2S) + SH(X2Π) reaction according to the TDWP method at the two collision energies (2.24 kcal/mol and 3.96 kcal/mol) displayed in Fig. 7. The experimental results5 and several theoretical results1620 are also shown in the figure. Because the theoretical results obtained from DMBE/CBS and DMBE/SEC PESs are relative in the paper of Hankel and co-workers20, the previous theoretical results have been scaled separately to make the value at 90° equal to our result for comparison. For the experimental results and all of the theoretical results, both forward and backward scattering can be observed in the reaction as expected for a reaction with a deep well and no barrier. The DCSs are not strictly backward-forward symmetric. At the collision energy of 2.24 kcal/mol, a slight forward preference is found in the experimental results, and the DCSs obtained from the new PES reproduce this feature well. However, other previous theoretical results, particularly the DCSs16 obtained from Ho PES, show an opposite preference. For the collision energy of 3.96 kcal/mol, the forward preference in the experiment results is more significant, and our results match the preference well. The DCSs obtained from DMBE/CBS and DMBE/SEC PESs show a significant backward preference, contrary to the experimental results.

Bottom Line: The calculated integral cross sections decrease with increasing collision energy and remain fairly constant within the high collision energy range.Both forward and backward scatterings can be observed as expected for a barrierless reaction with a deep well on the PES.The calculated integral cross sections and differential cross sections are in good agreement with the experimental results.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Materials Modification by Laser, Electron, and Ion Beams (Ministry of Education), School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024, PR China.

ABSTRACT
We constructed a new global potential energy surface (PES) for the electronic ground state ((1)A') of H2S based on 21,300 accurate ab initio energy points over a large configuration space. The ab initio energies are obtained from multireference configuration interaction calculations with a Davidson correction using basis sets of quadruple zeta quality. The neural network method is applied to fit the PES, and the root mean square error of fitting is small (1.68 meV). Time-dependent wave packet studies for the S((1)D) + H2(X(1)Σg(+)) → H((2)S) + SH(X(2)Π) reaction on the new PES are conducted to study the reaction dynamics. The calculated integral cross sections decrease with increasing collision energy and remain fairly constant within the high collision energy range. Both forward and backward scatterings can be observed as expected for a barrierless reaction with a deep well on the PES. The calculated integral cross sections and differential cross sections are in good agreement with the experimental results.

No MeSH data available.