Ab initio and DFT investigation of structures and energies of low-lying isomers of ZnxSex (x = 1-4) clusters

Structures and energies of low-lying isomers of ZnxSex (x  = 1-4) clusters have been explored with the B3LYP, MP2, and CCSD(T) methods using a basis set of 6-31G(d). Counterpoise (CP)-corrected single point energy calculations on the CP-B3LYP/6-31G(d)-optimized geometries indicate that a singlet Dnh (n = 2-4) isomers are lowest in energy in the respective ZnxSex (x = 2-4) clusters. We report the CP-corrected electronic, zero-point vibrational, thermal, and interaction energies, and geometrical parameters of the various isomers on the CP-B3LYP-optimized structures. The CP correction leads to significant reduction of the stabilization energy of clusters and lengthening of the intermolecular distance. A D3h Zn3Se3 complex and D4h and Td Zn4Se4 isomers having either a planar or tetrahedral geometry are found to be significantly stabilized owing to extensive bonding presumably involving ionic contribution.