The ab initio ground-state potential energy function of beryllium monohydride, BeH

Ground-state potential energy functions and vibration-rotation energy levels of beryllium lithium and its cation

The accurate ground-state potential energy functions of the beryllium lithium dimer, BeLi, and its cation, BeLi⁺ , have been determined from ab initio calculations using the multi-reference averaged coupled-pair functional (MR-ACPF) method in conjunction with the correlation-consistent core-valence basis sets up to septuple-zeta quality. The importance of the electron correlation beyond the MR-ACPF level of approximation, scalar relativistic, and adiabatic effects was discussed. For BeLi⁺ , the similar calculation was performed using the single-reference coupled-cluster method, up to the CCSDTQ level of approximation. The vibration-rotation energy levels of the two species were predicted to near the "spectroscopic" accuracy. Strangely enough, the predicted vibrational term values do not compare well with the recent experimental data for either BeLi or BeLi⁺ , with discrepancies reaching as much as 20-60 cm^-1 for highly excited vibrational levels.

Energetics and reactivity of small beryllium deuterides

Enthalpies and free energies of reaction for small neutral and charged beryllium deuterides BeD, BeD₂, and BeD₃ that have been calculated are reported for a temperature range of 0 K to 1000 K. We discuss probable dissociation channels and possible ways of producing BeD by localizing the relevant transition states and by calculating corresponding rate constants. BeD and BeD⁺ are found to be the most stable ones among the considered compounds. BeD₂ and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ {\mathrm{BeD}}_2^{+} $$\end{document}BeD2+ are more likely to decompose into Be^0,+ + D₂ than into BeD^0,+ + D. The metastable BeD₃ and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ {\mathrm{BeD}}_3^{+} $$\end{document}BeD3+ predominantly decompose into BeD^0,+ + D₂. In light of our results on the reaction energetics, we can interpret the pathways for production of BeD via BeD₂ and BeD₃ intermediates observed in molecular dynamics simulations.

Ab initio ground-state potential energy functions of beryllium monohydride ions: BeH+ and BeH-

The accurate ground-state potential energy functions of beryllium monohydride (BeH) cation and anion have been determined from ab initio calculations using the multi-reference averaged coupled-pair functional (MR-ACPF) method in conjunction with the correlation-consistent core-valence basis sets up to septuple-zeta quality. The effects of electron correlation beyond the MR-ACPF level of approximation, as well as the scalar relativistic and adiabatic corrections were taken into account. The vibration-rotation energy levels of the BeH, BeD, and BeT isotopologues of both ions were predicted to near "spectroscopic" accuracy. The results can be useful in a future experimental detection of the BeH anion by high-resolution vibration-rotation spectroscopy.