dorsal/arxiv
View SchemaAb initio calculations with a nonspherical Gaussian basis set: Excited states of the hydrogen molecule
| Authors | T. Detmer, P. Schmelcher, L. S. Cederbaum |
|---|---|
| Categories | |
| ArXiv ID | physics/9808017 |
| URL | https://arxiv.org/abs/physics/9808017 |
| DOI | 10.1063/1.477639 |
Abstract
A basis set of generalized nonspherical Gaussian functions (GGTOs) is presented and discussed. As a first example we report on Born-Oppenheimer energies of the hydrogen molecule. Although accurate results have been obtained, we conclude that H_2 is too 'simple' to allow for a substantial gain by using nonspherical functions. We rather expect that these functions may be particularly useful in calculations on large systems. A single basis set of GGTOs was used to simultaneously calculate the potential energy curves of several states within each subspace of {1,3}\Sigma_{g,u} symmetry. We hereby considerd the entire region of internuclear distances 0.8 < R < 1000 a.u. In particular the results for the fourth up to sixth electronic states show a high accuracy compared to calculations which invoke explicitely correlated functions, e.g. the relative accuracy is at least of the order of magnitude of 10^{-5}a.u. Energies for the 4 ^1\Sigma_u^+ and 4-6 ^3\Sigma_u^+ were improved and accurate data for the 6 ^3\Sigma_g^+, 5 ^1\Sigma_u^+, and 6 ^1\Sigma_u^+ state are, to the best of the authors knowledge, presented for the first time. Energy data for the seventh up to the nineth electronic state within each subspace were obtained with an estimated error of the order of magnitude of 10^{-4}a.u. The 7 ^1\Sigma_g^+ and the 6 ^1\Sigma_u^+ state were found to exhibit a very broad deep outer well at large internuclear distances.
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"abstract": "A basis set of generalized nonspherical Gaussian functions (GGTOs) is\npresented and discussed. As a first example we report on Born-Oppenheimer\nenergies of the hydrogen molecule. Although accurate results have been\nobtained, we conclude that H_2 is too \u0027simple\u0027 to allow for a substantial gain\nby using nonspherical functions. We rather expect that these functions may be\nparticularly useful in calculations on large systems. A single basis set of\nGGTOs was used to simultaneously calculate the potential energy curves of\nseveral states within each subspace of {1,3}\\Sigma_{g,u} symmetry. We hereby\nconsiderd the entire region of internuclear distances 0.8 \u003c R \u003c 1000 a.u. In\nparticular the results for the fourth up to sixth electronic states show a high\naccuracy compared to calculations which invoke explicitely correlated\nfunctions, e.g. the relative accuracy is at least of the order of magnitude of\n10^{-5}a.u. Energies for the 4 ^1\\Sigma_u^+ and 4-6 ^3\\Sigma_u^+ were improved\nand accurate data for the 6 ^3\\Sigma_g^+, 5 ^1\\Sigma_u^+, and 6 ^1\\Sigma_u^+\nstate are, to the best of the authors knowledge, presented for the first time.\nEnergy data for the seventh up to the nineth electronic state within each\nsubspace were obtained with an estimated error of the order of magnitude of\n10^{-4}a.u. The 7 ^1\\Sigma_g^+ and the 6 ^1\\Sigma_u^+ state were found to\nexhibit a very broad deep outer well at large internuclear distances.",
"arxiv_id": "physics/9808017",
"authors": [
"T. Detmer",
"P. Schmelcher",
"L. S. Cederbaum"
],
"categories": [
"physics.chem-ph"
],
"doi": "10.1063/1.477639",
"title": "Ab initio calculations with a nonspherical Gaussian basis set: Excited states of the hydrogen molecule",
"url": "https://arxiv.org/abs/physics/9808017"
},
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