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DOE OSTI2020

Materials Data on BeO2 by Materials Project

BeO2 is quartz (alpha)-like structured and crystallizes in the monoclinic P2_1 space group. The structure is two-dimensional and consists of one BeO2 sheet oriented in the (0, 0, 1) direction. there are six inequivalent Be sites. In the first Be site, Be is bonded to four O atoms to form corner-sharing BeO4 tetrahedra. There are a spread of Be–O bond distances ranging from 1.57–1.62 Å. In the second Be site, Be is bonded to four O atoms to form corner-sharing BeO4 tetrahedra. There is two shorter (1.58 Å) and two longer (1.62 Å) Be–O bond length. In the third Be site, Be is bonded to four O atoms to form corner-sharing BeO4 tetrahedra. There are a spread of Be–O bond distances ranging from 1.57–1.62 Å. In the fourth Be site, Be is bonded to four O atoms to form corner-sharing BeO4 tetrahedra. There are a spread of Be–O bond distances ranging from 1.58–1.63 Å. In the fifth Be site, Be is bonded to four O atoms to form corner-sharing BeO4 tetrahedra. There are a spread of Be–O bond distances ranging from 1.58–1.62 Å. In the sixth Be site, Be is bonded to four O atoms to form corner-sharing BeO4 tetrahedra. There are a spread of Be–O bond distances ranging from 1.58–1.62 Å. There are twelve inequivalent O sites. In the first O site, O is bonded in a bent 150 degrees geometry to two Be atoms. In the second O site, O is bonded in a bent 150 degrees geometry to two Be atoms. In the third O site, O is bonded in a bent 150 degrees geometry to two Be atoms. In the fourth O site, O is bonded in a bent 150 degrees geometry to two Be atoms. In the fifth O site, O is bonded in a bent 150 degrees geometry to two equivalent Be atoms. In the sixth O site, O is bonded in a bent 150 degrees geometry to two Be atoms. In the seventh O site, O is bonded in a distorted bent 120 degrees geometry to two Be atoms. In the eighth O site, O is bonded in a bent 150 degrees geometry to two Be atoms. In the ninth O site, O is bonded in a bent 150 degrees geometry to two equivalent Be atoms. In the tenth O site, O is bonded in a bent 150 degrees geometry to two Be atoms. In the eleventh O site, O is bonded in a bent 150 degrees geometry to two Be atoms. In the twelfth O site, O is bonded in a bent 120 degrees geometry to two Be atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on BeO2 by Materials Project

BeO2 is quartz (alpha)-like structured and crystallizes in the orthorhombic P2_12_12_1 space group. The structure is three-dimensional. Be is bonded to four O atoms to form corner-sharing BeO4 tetrahedra. There is two shorter (1.59 Å) and two longer (1.60 Å) Be–O bond length. There are two inequivalent O sites. In the first O site, O is bonded in a bent 150 degrees geometry to two equivalent Be atoms. In the second O site, O is bonded in a bent 150 degrees geometry to two equivalent Be atoms.

36 MATERIALS SCIENCE↗

NASA NTRS1992

Theoretical study of the alkaline-earth metal superoxides BeO2 through SrO2

Three competing bonding mechanisms have been identified for the alkaline-earth metal superoxides: these result in a change in the optimal structure and ground state as the alkaline-earth metal becomes heavier. For example, BeO2 has a linear 3Sigma(-)g ground-state structure, whereas both CaO2 and SrO2 have C(2v)1A1 structures. For MgO2, the theoretical calculations are less definitive, as the 3A2 C(2v) structure is computed to lie only about 3 kcal/mol above the 3Sigma(-)g linear structure. The bond dissociation energies for the alkaline-earth metal superoxides have been computed using extensive Gaussian basis sets and treating electron correlation at the modified coupled-pair functional or coupled-cluster singles and doubles level with a perturbational estimate of the triple excitations.

Bauschlicher, Charles W., Jr.↗

NASA NTRS1992

Comparison of the Brueckner and coupled-cluster approaches to electron correlation

The coupled-cluster and Brueckner electron correlation methods are used to determine the equilibrium structures, dipole moments, harmonic vibrational frequencies, and IR intensities of NH3, FON, Be3, BeC2, and BeO2. The singles and doubles coupled-cluster and Brueckner doubles methods are employed, and the corresponding methods that include a perturbational estimate of connected triple excitations are also investigated. The T sub 1 diagnostic is found to provide a good indication of the magnitude of the difference between the results obtained with the coupled-cluster and Brueckner methods. For NH3, the T sub 1 diagnostic is small and so the differences between results obtained from coupled-cluster and Brueckner theories are quite small. It is found for all of the molecules under consideration that inclusion of the contribution from connected triple excitations is more important than the differences between the Brueckner and coupled-cluster correlation methods.

Lee, Timothy J.↗