Allowed and Forbidden Reaction Paths for the H2 + D2 Exchange Reaction

1975 ◽  
Vol 53 (4) ◽  
pp. 549-555 ◽  
Author(s):  
James S. Wright

Symmetry arguments and abinitio s.c.f. calculations (double-zeta basis set) are used to show that the exchange reaction H2+ D2 → 2HD could proceed in a concerted fashion through a six-center transition state. The computed barrier height of 90 kcal/mol for this process lies below the experimental dissociation energy of H2 (but above the computed dissociation energy) and also below the energy required for exchange through a four-center transition state. Either the termolecular(2 + 2 + 2 ) or bimolecular(4 + 2 ) cycloadditions are thermally allowed. The presence of a transition metal would allow the reaction to proceed through a four-center geometry, leading to the formation of a possibly stable metal-H4 complex.

1988 ◽  
Vol 43 (2) ◽  
pp. 143-146
Author(s):  
Supot V. Hannongbua ◽  
Sirirat U. Kokpol ◽  
Suchada Kreawsrikul ◽  
Supa Polman ◽  
Bernd M. Rode

The intermolecular interaction for ammonia-lithium ion has been investigated based on the LCAO-MO-SCF method, with double zeta basis set including polarization. The potential functions were constructed firstly from 50 ammonia configuration. Then 50 additional random configurations were added to test the quality of the function. The results show that even 100 configurations are not enough to obtain convergency, but the quality of the function obtained by well-selected points of the surface is already sufficient for simulation purposes.


1981 ◽  
Vol 79 (2) ◽  
pp. 202-204 ◽  
Author(s):  
Paul Saxe ◽  
Henry F. Shaefer ◽  
Nicholas C. Handy

1981 ◽  
Vol 36 (2) ◽  
pp. 279-281 ◽  
Author(s):  
Herman Teeninga ◽  
Wim C. Nieuwpoort ◽  
Jan B. F. N. Engberts

Abstract The relative magnitude of the nitrogen hyperfine splitting constants of sulfonamidyls and carboxamidyls is rationalized in terms of the results of ab initio MO calculations using the "double zeta" basis set of Roos and Siegbahn.


1986 ◽  
Vol 39 (5) ◽  
pp. 711 ◽  
Author(s):  
PD Gray ◽  
PG Burton

A previously reported full CI (configuration interaction) extrapolation procedure based on multireference single and double CI, which gave excellent results for H20 at the equilibrium geometry, is extended to two other geometries for which explicit full CI results are known. The technique is shown to provide good results for cases where the SCF (self-consistent field) configuration is not strongly dominant, although degradation of performance is noticeable in these cases. The technique is also used to predict a full CI result for the 21 Al state of H20 with the double zeta basis.


2019 ◽  
Author(s):  
Mark Iron ◽  
Trevor Janes

A new database of transition metal reaction barrier heights – MOBH35 – is presented. Benchmark energies (forward and reverse barriers and reaction energy) are calculated using DLPNO-CCSD(T) extrapolated to the complete basis set limit using a Weizmann1-like scheme. Using these benchmark energies, the performance of a wide selection of density functional theory (DFT) exchange–correlation functionals, including the latest from the Truhlar and Head-Gordon groups, is evaluated. It was found, using the def2-TZVPP basis set, that the ωB97M-V (MAD 1.8 kcal/mol), ωB97X-V (MAD 2.1 kcal/mol) and SCAN0 (MAD 2.1 kcal/mol) hybrid functionals are recommended. The double-hybrid functionals PWPB95 (MAD 1.6 kcal/mol) and B2K-PLYP (MAD 1.8 kcal/mol) did perform slightly better but this has to be balanced by their increased computational cost.


1995 ◽  
Vol 102 ◽  
pp. 65 ◽  
Author(s):  
Struan H. Robertson ◽  
Albert F. Wagner ◽  
David M. Wardlaw

2015 ◽  
Vol 2 (3) ◽  
pp. 201-205 ◽  
Author(s):  
Yukiteru Ito ◽  
Mitsuhiro Yoshimatsu

Regioselective H/D exchange reaction of functional groups on heterocycles proceeded via a transition metal-free reductive cyclization of sulfanyl 1,6-diynes using sodium borodeuteride/ethanol-D1.


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