Description

This research reports a search for peculiar monobridged structures of the E2H2 molecules (E = Be, Mg, Ca, Sr, Ba). For Be2H2 and Mg2H2, the monobridged geometry is not an equilibrium but rather a transition state between the vinylidene-like structure and the global minimum HE–EH linear geometry. However, for Ca2H2, Sr2H2, and Ba2H2, this situation changes significantly; the linear structure is no longer the global minimum but lies higher in energy than two other equilibria, the dibridged and monobridged structures. The planar dibridged structures of both Sr2H2 and Ba2H2 should be observable via IR spectroscopy. Although the remarkable monobridged structures lie 8.3 (Sr) and 7.6 kcal/mol (Ba) higher, the large IR intensities of the terminal E–H stretching frequencies may make the monobridged structures observable. The monobridged structures have sizable permanent dipole moments (3.07 and 3.06 D for Sr and Ba, respectively) and also should be observable via microwave spectroscopy.

OCLC

1259518063

Document Type

Dataset

DCMI Type

Dataset

File Format

.zip, .txt, .log, .in, .out, .data, .molden, .pdf

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Publication Date

6-16-2021

Funder

NSF, Division of Chemistry (CHE)

Publisher

Utah State University

Award Number

NSF, Division of Chemistry (CHE) 1664379

Award Title

Deciphering Delocalized Bonding in Excited States, Solvated Species and Novel 0-, 1-, 2-, and 3-Dimensional Chemical Systems

Methodology

The search for the global minimum of Be2H2, Mg2H2, and Ca2H2 at singlet states was performed using the Coalescence Kick program (10,000 trial structures for each stoichiometry) at the PBE0/3-21G level of theory. The lowest in energy isomers then were reoptimized at PBE0/6-311++G** and CCSD(T)/cc-pVQZ levels. The Gaussian-16 software was used for the geometry optimization and frequency calculations. In order to assess the multireference character of wavefunctions of investigated systems, the CASSCF/cc-pvqz (for Be, Mg, and Ca containing structures) and CASSCF/def2qzvp (for Sr and Ba containing structures) calculations were performed via the ORCA software. The active space was chosen in such a way, to account for all valence electrons and six lowest unoccupied molecular orbitals (6e, 9o). The PBE0/cc-qcvp wavefunctions were chosen as initial guesses for those calculations. The geometries obtained at the CCSD(T)/cc-pvqz level were used, the ZPE correction was taken into account using values calculated at the CCSD(T)/cc-pvqz level. Dynamical correlation is added through the second-order N-electron valence state perturbation theory (NEVPT2) method. The chemical bonding pattern was analyzed using the AdNDP 2.0 code at PBE0/6-311++G** level of theory.

Referenced by

Narendrapurapu, B. S., Bowman, M. C., Xie, Y., Schaefer, H. F., Tkachenko, N. V., Boldyrev, A. I., & Li, G. (2020). Dibridged, Monobridged, Vinylidene-Like, and Linear Structures for the Alkaline Earth Dihydrides Be 2 H 2 , Mg 2 H 2 , Ca 2 H 2 , Sr 2 H 2 , and Ba 2 H 2. Proposals for Observations. Inorganic Chemistry, 59(15), 10404–10408. https://doi.org/10.1021/acs.inorgchem.0c01651

Language

eng

Code Lists

N/A

Comments

Total 132 data files are included, zipped into their original directories. Chemical bonding analysis files, Supplementary information file.

Disciplines

Chemistry

License

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.

Identifier

https://doi.org/10.15142/0bt0-m063

Checksum

0addd9525b31135dcf7a639d72c54009

Additional Files

README.txt (3 kB)
MD5: 98e899530e6c7e31595a19313f24fe46

AdNDP_Be2H2.zip (622 kB)
MD5: 73fadcc48edaefcce8bfc849a20097a3

AdNDP_Ca2H2.zip (990 kB)
MD5: 48f96232a492205528ead34a9c5be1bf

AdNDP_Mg2H2.zip (805 kB)
MD5: 4df3e91c11243c823a20dd9fb5a4e40b

Supporting_Information.pdf (456 kB)
MD5: fd87a59ce63a5a465a7afed86dc8c200

Included in

Chemistry Commons

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