Iv. Ovcharenko et al., Quantum Monte Carlo characterization of small Cu-doped silicon clusters: CuSi4 and CuSi6, J CHEM PHYS, 114(20), 2001, pp. 9028-9032
The relative energies, binding energies, and adsorption energies of three C
uSi4 and two CuSi6 clusters have been computed in the fixed-node diffusion
Monte Carlo (FNDMC), CASSCF, and B3LYP DFT methods. These results are compa
red with the earlier Hartree-Fock (HF) and B3LYP DFT investigations of thes
e systems by two of us [C. Xiao and F. Hagelberg, J. Mol. Struct.: THEOCHEM
529, 241 (2000)]. The very close energy level spacing of the isomers under
consideration confirms the previous work of Xiao and Hagelberg. The FNDMC
results show some qualitative discrepancies with B3LYP DFT, and HF findings
. They also confirm the appropriateness of the B3LYP DFT method for the pre
diction of the most stable CuSi4 isomer, while the CASSCF method compares m
ore favorably with FNDMC for adsorption energies than B3LYP DFT. (C) 2001 A
merican Institute of Physics.