AB-INITIO INVESTIGATION ON STABILITY AND PROPERTIES OF XYCO-CENTER-DOT-CENTER-DOT-CENTER-DOT-HZ COMPLEXES .2. POST-HARTREE-FOCK STUDIES ON H2CO-CENTER-DOT-CENTER-DOT-CENTER-DOT-HF

Ab initio MP2 level of theory in conjunction with three basis sets of a triple-zeta quality was applied to study the molecular geometry and stability of the H2CO ... HF complex. An interaction energy predicted for this system at the highest, MP4(SDTQ)/6-311++G(2df, 2pd)//MP2/6-31 1++G(2df, 2pd), level corrected for the BSSE and ZPE contributions amo unts to -4.85 kcal/mol. BSSE contributes significantly to the interact ion energies at all applied levels. Reliable MP2/6-311++G(2df, 2pd) le vel harmonic vibrational frequencies, IR intensities, and the predicte d isotopic shifts upon deuteration and O-18 substitution are presented in order to facilitate experimental studies on the IR spectrum of the title complex.