Origin of the dimerization energy of BH3 to B2H6

Gélus, M.; Ahlrichs, Reinhart; Staemmler, Volker; Kutzelnigg, Werner

doi:10.1016/0009-2614(70)80159-2

Cited by 40 publications

(17 citation statements)

References 15 publications

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“…The dissociation energy obtained in the "small basis" (18.6 kcal/mole) is somewhat smaller than the one obtained by Buenker et al [I (d)] (19.7 kcal/mole). The "larger basis" lowers the dimerization energy to 11.5 kcal/mole which is closer to the value obtained by Gelus et al [2] (8.4 kcal/mole) . I t seems safe to draw the conclusion that the SCF part of the dimerization energy is on the order of 10-20 kcal/mole.…”

Section: B Scf Resultssupporting

confidence: 82%

“…The one-electron energies, together with the total energies, are shown in [2], who get -26.3821 a.u.…”

Section: B Scf Resultsmentioning

confidence: 99%

“…The present calculation utilized a set of all s-type Gaussians. Guided by experience on similar systems, we made the following choice of basis for the linear expansion of the self-consistent molecular orbitals: for the hydrogens we used Huzinaga's [3] 3-s functions scaled by a factor of 1.8 [4], the boron s-orbitals used were the 7-s functions given by Whitman and Hornback [5] contracted to (4, 1, 1, 1) groups, the #-orbitals on boron used a hydrogen atom 3-p expansion given by Whitten [6] and appropriately scaled by the Slater effective charge and contracted to (2,1) groups.…”

Section: A Basis Setsmentioning

confidence: 99%

“…After completing the present work, we learned about recent calculations [2] which claim that the dimerization energy has a surprisingly large contribution from the so-called "correlation energy." Our results partly support this conclusion, but a reliable Hartree-Fock limit for B2H6 is needed before this interesting question really can be settled.…”

Section: Introductionmentioning

confidence: 98%

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On the dimerization of BH₃ and the associated delocalization (resonance) energy

Edmiston

Lindner

1973

Int J of Quantum Chemistry

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AbstractsSCF calculations utilizing a basis of all s-type Gaussians have been performed to investigate the dimerization of BH, to B,H,. Localized molecular orbitals and pseudonatural orbitals are calculated. The dimerization energy obtained (1 1.5 kcal/mole) supports the assumption that the non-Hartree-Fock interactions (electron correlation) play a dominant role (Exp = 40-60 kcal/mole).The energy of the principal type of resonance structure based on the SCP-MO'S of theH H H separated-but-distorted BH, systems is rigorously calculated and found to be 150 kcal/mole higher in energy than the SCF energy of B,H,. Thus, resonance stabilization (delocalization) is shown to be extremely important to the stability of the "three-center" bonds in B,H,, as has been suspected for many years.

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Section: B Scf Resultssupporting

confidence: 82%

“…The one-electron energies, together with the total energies, are shown in [2], who get -26.3821 a.u.…”

Section: B Scf Resultsmentioning

confidence: 99%

Section: A Basis Setsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

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On the dimerization of BH₃ and the associated delocalization (resonance) energy

Edmiston

Lindner

1973

Int J of Quantum Chemistry

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“…[15][16][17][18][19][20][21][22] Perhaps the most powerful method of doing so is to use frozen natural orbitals ͑FNOs͒. 18,20,[23][24][25][26][27][28] These orbitals use information from an approximate one-particle reduced density matrix to choose the best subset of one-particle orbitals within which to perform a correlated calculation. When using FNOs based on the MBPT͑2͒ density matrix, 29,30 this truncated orbital set has been shown to be surprisingly effective at truncating larger basis sets, allowing ϳ50% of a modified unoccupied orbital set to be removed without significant changes to ground state CC energies and density matrices.…”

Section: Introductionmentioning

confidence: 99%

Frozen natural orbital coupled-cluster theory: Forces and application to decomposition of nitroethane

Taube

Bartlett

2008

The Journal of Chemical Physics

114

128

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The frozen natural orbital ͑FNO͒ coupled-cluster method increases the speed of coupled-cluster ͑CC͒ calculations by an order of magnitude with no consequential error along a potential energy surface. This method allows the virtual space of a correlated calculation to be reduced by about half, significantly reducing the time spent performing the coupled-cluster ͑CC͒ calculation. This paper reports the derivation and implementation of analytical gradients for FNO-CC, including all orbital relaxation for both noncanonical and semicanonical perturbed orbitals. These derivatives introduce several new orbital relaxation contributions to the CC density matrices. FNO-CCSD͑T͒ and FNO-⌳CCSD͑T͒ are applied to a test set of equilibrium structures, verifying that these methods are capable of reproducing geometries and vibrational frequencies accurately, as well as energies. Several decomposition pathways of nitroethane are investigated using CCSD͑T͒ and ⌳CCSD͑T͒ with 60% of the FNO virtual orbitals in a cc-pVTZ basis, and find differences on the order of 5 kcal/ mol with reordering of the transition state energies when compared to B3LYP 6-311 +G͑3df ,2p͒.

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