Dynamically corrected ab initio minimum geometries and NMR chemical shifts for H-bonded systems

Anharmonic potential energy surfaces for the coordinates r(A-H) and r(A...B) in the A-H...B H-bonds (H2O)(2), HOHF-, and HOHOH- have been calculated ab initio. In addition, NMR nuclear shielding surfaces for the atoms A and B were calculated. The nuclear configuration interaction (CI) method was applied to achieve anharmonic vibrational states. These are the bases for the vibrationally averaged distances r(A-H) and r(A-D) as well as r(A...B)(H) and r(A...B)(D), and dynamically corrected NMR chemical shifts. Changes of interatomic distances and chemical shifts upon deuteration are presented and discussed. The maximum dynamical corrections are 0.09 Angstrom for the OH distance in HOHOH- and 9 ppm for delta(F-19) in HOHF-. The maximum deuteration effects are 0.018 Angstrom for the OH distance and 3 ppm for the delta(F-19) NMR chemical shift in HOHF-.