Electron correlation theories and their application to the study of simple reaction potential surfaces

Pople, John A.; Krishnan, R.; Schlegel, H. Bernhard; Binkley, J. Stephen

doi:10.1002/qua.560140503

Cited by 1,021 publications

(375 citation statements)

References 12 publications

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“…For both the CCSD͑T͒ and CASPT2 calculations, the TZVP-G͑3df ,2p͒ basis set described above were used. CCSD͑T͒ is a coupled-cluster method, 42,43 which uses single and double excitations from the Hartree-Fock determinant, [44][45][46][47] and includes triple excitations noniteratively. 48 Finally, CASPT2 ͑Refs.…”

Section: Methodsmentioning

confidence: 99%

Quantum Monte Carlo study of the ground state and low-lying excited states of the scandium dimer

Matxain

Rezabal

López

et al. 2008

The Journal of Chemical Physics

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A large set of electronic states of scandium dimer has been calculated using high-level theoretical methods such as quantum diffusion Monte Carlo ͑DMC͒, complete active space perturbation theory as implemented in GAMESS-US, coupled-cluster singles, doubles, and triples, and density functional theory ͑DFT͒. The 3 ⌺ u and 5 ⌺ u states are calculated to be close in energy in all cases, but whereas DFT predicts the 5 ⌺ u state to be the ground state by 0.08 eV, DMC and CASPT2 calculations predict the 3 ⌺ u to be more stable by 0.17 and 0.16 eV, respectively. The experimental data available are in agreement with the calculated frequencies and dissociation energies of both states, and therefore we conclude that the correct ground state of scandium dimer is the 3 ⌺ u state, which breaks with the assumption of a 5 ⌺ u ground state for scandium dimer, believed throughout the past decades.

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Section: Methodsmentioning

confidence: 99%

Quantum Monte Carlo study of the ground state and low-lying excited states of the scandium dimer

Matxain

Rezabal

López

et al. 2008

The Journal of Chemical Physics

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“…The canonical MO ͑CMO͒ NICS values are also calculated for the low-lying isomers of Si and Ge using the NBO 5.0 program. 19 Last, to determine the lowest-energy structure among top candidate isomers of Si and Ge obtained from step 2, the single-point energy calculation using the coupled-cluster method with single, double, and perturbative triple excitations 20 ͓CCSD͑T͔͒ and with a larger and more diffusive 6-311+ G͑2d͒ basis set for Si and the same 6-31+ G͑d͒ basis set for Ge is performed, based on geometric structures optimized at the MP2 / 6-31+ G͑d͒ level of theory/basis set.…”

Section: Computational Detailsmentioning

confidence: 99%

“…The TTP motif is known as one of major structural motifs in low-energy silicon clusters of Si 10 -Si 20 . 22 Indeed, among the top ten low-lying isomers of Si 12 2− , six contain the TTP motif ͑highlighted in Table I͒.…”

Section: A Si 12 2−mentioning

confidence: 99%

Search for lowest-energy structure of Zintl dianion Si122−, Ge122−, and Sn122−

Shao

Bulusu

Zeng

2008

The Journal of Chemical Physics

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We perform an unbiased search for the lowest-energy structures of Zintl dianions ͑Si 12 2− , Ge 12 2− , and Sn 12 2− ͒, by using the basin-hopping ͑BH͒ global optimization method combined with density functional theory geometric optimization. High-level ab initio calculation at the coupled-cluster level is used to determine relative stabilities and energy ranking among competitive low-lying isomers of the dianions obtained from the BH search. For Si 12 2− , all BH searches ͑based on independent initial structures͒ lead to the same lowest-energy structure Si 12a 2− , a tricapped trigonal prism ͑TTP͒ with C s group symmetry. Coupled-cluster calculation, however, suggests that another

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“…A disadvantage of the MP method is that the computation converges slowly for heavy elements, and this can lead to inaccurate energies [124]. The problem of convergence is reduced with the coupled cluster (CC) methods [125,126]. The CC methods start with the HF method and construct multi-electron wave functions making use of the exponential cluster operator to account for CI.…”

Section: Quantum Mechanical Methodsmentioning

confidence: 99%

Assessment of theoretical methods for the study of hydrogen abstraction kinetics of global warming gas species during their degradation and byproduct formation (IUPAC Technical Report)

Ramasami

Abdallah

Archibong

et al. 2013

Pure and Applied Chemistry

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Global climate change is a major concern as it leads to an increase in the average temperature of the earth's atmosphere. The existence and persistence of some gaseous species in the atmosphere contribute to global warming. Experimental techniques are used to study the kinetics and degradation of global warming gases. However, quantum mechanical methods are also useful for the kinetic and radiative forcing study of global warming species and can precede experimental investigations. Research has also been targeted to develop more adapted procedures using ab initio and density functional theory (DFT) methods. This report provides a global perspective, in simplified manner, of the theoretical studies of the degradation of gas species in the atmosphere with an emphasis on the hydrogen abstraction kinetics of global warming gas species during their degradation and byproduct formation. En route, the results obtained from these studies are analysed and compared with experimental data where available. Our analyses indicate that the theoretical predictions are in agreement with experimental findings but the predicted parameters are dependent on the method being used. Theoretical methods are used to predict the thermodynamic parameters of reactions, and, with relevance to this report, the global warming potential (GWP) index can also be calculated. This report can be useful for future investigations involving global warming gaseous species while providing suggestions on how computations can fill in data gaps when experimental data are unavailable.

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Electron correlation theories and their application to the study of simple reaction potential surfaces

Cited by 1,021 publications

References 12 publications

Quantum Monte Carlo study of the ground state and low-lying excited states of the scandium dimer

Quantum Monte Carlo study of the ground state and low-lying excited states of the scandium dimer

Search for lowest-energy structure of Zintl dianion Si122−, Ge122−, and Sn122−

Assessment of theoretical methods for the study of hydrogen abstraction kinetics of global warming gas species during their degradation and byproduct formation (IUPAC Technical Report)

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