Bonding in Beryllium Clusters

Abstract

Beryllium clusters provide an ideal series for exploring the evolution from discrete molecules to the metallic state. The beryllium dimer has a formal bond order of zero, but the molecule is weakly bound. In contrast, bulk-phase beryllium is a hard metal with a high melting point. Theoretical calculations indicate that the bond energies increase dramatically for Be(n) clusters in the range n=2-6. A triplet ground state is found for n=6, indicating an early emergence of metallic properties. There is an extensive body of theoretical work on smaller Be(n) clusters, in part because this light element can be treated using high-level methods. However, the apparent simplicity of beryllium is deceptive, and the calculations have proved to be challenging owing to strong electron correlation and configuration interaction effects. Consequently, these clusters have become benchmark systems for the evaluation of a wide spectrum of quantum chemistry methods.

Ab initio study of many-body decomposition of the interaction energy in small beryllium clusters

“…Analysis of the stability of Be complexes was performed several years ago by Lee et al [10]. Detailed decomposition of the total IE was performed more recently by Bondybey and coworkers [3,11,12]. Energy analysis of the hydrogen trapped in Be clusters was studied recently.…”

“…In fact, Be atom in a Be cluster is chemically quite different from the separated one. This is related to low 2s-2p excitation energy of Be that allows creation of s-p hybrid orbitals (see the analysis by Heaven et al [12]). Therefore, a beryllium cluster (Be n , n > 3) is more like a molecule with strong covalent bonds, rather than a noncovalent complex composed of 'individual' Be atoms.…”

Adsorption of beryllium atoms and clusters both on graphene and in a bilayer of graphite investigated by DFT

“…Another consequence of the small 2s-2p energy interval is that the ground state of simple beryllium compounds is often multi-reference in nature, which is very challenging in computational chemistry. Many beryllium aggregates have also been investigated, like the Be 3 trimer [16,17] or bigger Be n clusters, with n up to 9, some of them at the MP4 [16] or FCI levels [17], some other with DFT [18][19][20].…”

State-to-state inelastic scattering of Stark-decelerated OH radicals with Ar atoms

“…33,34 Detailed information on the OH(X 2 P)-Ar PES has also been obtained from spectroscopic study of the bound states of the OH-Ar van der Waals complex. 35,36 Here we report the investigation of rotational energy transfer of fully state-selected OH (X 2 P 3/2 , J = 3/2, f) radicals in collisions with Ar atoms at collision energies between 80 and 800 cm…”