			15min:

PREDICTION OF FUNDAMENTAL VIBRATIONAL FREQUENCIES AND INFRARED INTENSITIES:
A BENCHMARK STUDY.

JUANA VÁZQUEZ, MICHAEL E. HARDING, JOHN F. STANTON, Institute for Theoretical Chemistry, Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, TX 78712 .

In this work we investigate the performance of second-order vibrational perturbation theory (VPT2) using force fields computed at the fc-CCSD(T) level in conjunction with different double-, triple-, and quadruple- zeta basis sets\footnoteAtomic natural orbital (ANOY, Y=0,1,2) [J. Almlöf and P. R. Taylor, J. Chem. Phys. 86, 4070 (1987)] and correlation-consistent (cc-pVXZ, X=D,T,Q) [T. H. Dunning, Jr., J. Chem. Phys. 90, 1007 (1989)] basis sets. for the prediction of fundamental vibrational frequencies and infrared intensities. A benchmark study comprising more than thirty small and medium sized molecules illustrates the accuracy and limitations of the presented scheme.