RHF Ab initio electronic and molecular structures of a ((SINGLEBOND)Be2(SINGLEBOND))? chain

Abstract

Ab initio RHF/STO-3G, 3-21~, and 6-31~ band structure calculations were carried out on an extended regular chain of beryllium atoms (--Bez-)= to study its stability in comparison with corresponding data on finite chains and previously reported results on small elemental beryllium clusters. It is found that, starting from a linear distribution of atoms along the chain, the system evolves toward a regular zigzag planar structure. The total RHF energy per constituent atom is higher for the chains than for the clusters and is thereby suggestive of that isolated chains are unlikely to exist except in constraining channels of host structures. In the limit of the infinite chain, there are signs indicating that the RHF model is no longer an adequate description. 0 1996 John Wiley & Sons, Inc.

Exchange contributions in the electronic structure of systems with 1D‐periodicity: Importance and computation

“…To illustrate the situation we have carried out direct space calculations with the PLH program 23 on the trivially simple infinite chain of Be atoms, (‐Be‐) ∞ , using the rather common and somewhat limited 3‐21G basis set. The unit cell length a 0 was arbitrarily set equal to 0.232 nm, a value based on previous calculations on Be clusters 24. The number of explicitly interacting cells on each side of the reference unit cell was set to 10, and the number of cells used in the intermediate region to correct for the long‐range coulombic interactions was set to 49 (for more details about the meaning of these parameters see Ref.…”