Calculation of STOs electron repulsion integrals by ellipsoidal expansion and large-order approximations

Lesiuk, Michał

doi:10.1007/s10910-015-0576-5

Cited by 10 publications

(6 citation statements)

References 48 publications

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“…In this paper we expand upon our previous work where the interaction energy of the beryllium dimer at the minimum of the potential energy curve has been determined with help of the Slater-type orbitals , by using the newly developed programs. − We largely extend the results reported previously and calculate the full potential energy curve (PEC) including corrections due to the adiabatic, relativistic, and quantum electrodynamics effects. Next, we generate analytic fits of the interaction potentials and solve the nuclear Schrödinger equation to obtain the vibrational energy terms.…”

Section: Introductionmentioning

confidence: 89%

Ab initio Potential Energy Curve for the Ground State of Beryllium Dimer

Lesiuk

Przybytek

Balcerzak

et al. 2019

J. Chem. Theory Comput.

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This work concerns ab initio calculations of the complete potential energy curve and spectroscopic constants for the ground state X 1 Σ + g of the beryllium dimer, Be 2 .High accuracy and reliability of the results is one of the primary goals of the paper. To this end we apply large basis sets of Slater-type orbitals combined with highlevel electronic structure methods including triple and quadruple excitations. The effects of the relativity are also fully accounted for in the theoretical description. For the first time the leading-order quantum electrodynamics effects are fully incorporated for a many-electron molecule. Influence of the finite nuclear mass corrections (post-Born-Oppenheimer effects) turns out to be completely negligible for this system. The predicted well-depth (D e = 934.5 ± 2.5 cm −1 ) and the dissociation energy (D 0 = 808.0 cm −1 ) are in a very good agreement with the most recent experimental data. We confirm the existence of the weakly bound twelfth vibrational level [Patkowski et al., Science 326, 1382(2009] and predict that it lies just about 0.5 cm −1 below the onset of the continuum.

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Section: Introductionmentioning

confidence: 89%

Ab initio Potential Energy Curve for the Ground State of Beryllium Dimer

Lesiuk

Przybytek

Balcerzak

et al. 2019

J. Chem. Theory Comput.

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“…Computer codes for the STO integrals, described in Refs. [37][38][39], were used in all relevant calculations.…”

Section: A Clamped-nucleus Nonrelativistic Polarizabilitymentioning

confidence: 99%

Theoretical determination of polarizability and magnetic susceptibility of neon

Lesiuk,

Przybytek,

Jeziorski

2020

Preprint

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We report theoretical determination of the dipole polarizability of the neon atom, including its frequency dependence. Corrections for the relativistic, quantum electrodynamics, finite nuclear mass, and finite nuclear size effects are taken into account. We obtain the value α0 = 2.66080(36) for the static polarizability, and α2 = 2.850(7) and α4 = 4.932(14) for the first two polarizability dispersion coefficients (Cauchy moments); all values are in atomic units (a.u.). In the case of static polarizability, our result agrees with the best experimental determination [C. Gaiser and B. Fellmuth, Phys. Rev. Lett. 120, 123203 (2018)], but our estimated uncertainty is significantly larger. For the dispersion coefficients, the results obtained in this work appear to be the most accurate to date overall compared to published theoretical and experimental data. We also calculated the static magnetic susceptibility of the neon atom, needed to obtain the refractive index of gaseous neon. Our result, χ0 = −8.484(19) • 10 −5 a.u., is about 9% larger in absolute value than the recommended experimental value [CRC Handbook of Chemistry and Physics, CRC Press, 2019, p. 4-145].

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“…We combine high-level quantum chemical methods with large one-electron basis sets composed of Slater-type orbitals (STOs) [70,71] to reach saturation of the calculated values. We employ techniques for calculation of the twocenter matrix elements over STOs reported recently [72][73][74][75][76]. Moreover, we evaluate corrections arising from several minor physical effects, e.g., adiabatic or relativistic.…”

Section: Introductionmentioning

confidence: 99%

Potential energy curve for the $a^3Σ_u^+$ state of lithium dimer with Slater-type orbitals

Lesiuk,

Musiał,

Moszynski

2020

Preprint

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We report state-of-the-art ab initio calculations of the potential energy curve for the a 3 Σ + u state of the lithium dimer conducted to achieve spectroscopic accuracy (<1cm −1 ) without any prior adjustment to fit the corresponding experimental data. The nonrelativistic clamped-nuclei component of the interaction energy is calculated with a composite method involving six-electron coupled cluster and full configuration interaction theories combined with basis sets of Slater-type orbitals ranging in quality from double-to sextuple-zeta. To go beyond the nonrelativistic Born-Oppenheimer picture we include both the leading-order relativistic and adiabatic corrections, and find both of these effects to be non-negligible within the present accuracy standards. The potential energy curve developed by us allowed to calculate molecular parameters (De, D0, ωe etc.) for this system, as well as the corresponding vibrational energy levels, with an error of only a few tenths of a wavenumber (0.2 − 0.4 cm −1 ). We also report an ab initio value for the scattering length of two 2 S lithium atoms which determines the stability of the related Bose-Einstein condensate.

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Calculation of STOs electron repulsion integrals by ellipsoidal expansion and large-order approximations

Cited by 10 publications

References 48 publications

Ab initio Potential Energy Curve for the Ground State of Beryllium Dimer

Ab initio Potential Energy Curve for the Ground State of Beryllium Dimer

Theoretical determination of polarizability and magnetic susceptibility of neon

Potential energy curve for the $a^3Σ_u^+$ state of lithium dimer with Slater-type orbitals

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