Ab initio study of the cyclopropane–hydrogen fluoride dimer

Abstract

Ab initio results are reported for the cyclopropane–hydrogen fluoride dimer using a double-zeta plus polarization basis set. Agreement is found with experiment as regards the preferred geometry. The calculated hydrogen-bond length is somewhat overestimated at the restricted Hartree–Fock level. On the inclusion of electron correlation effects, via second-order Møller–Plesset perturbation theory, the hydrogen-bond length shortens and is in good agreement with that observed experimentally. The zero-point dissociation energy is predicted to be 4.3 kJ mol^–1 at the RHF level and 14.7 kJ mol^–1 at the MP2 level, suggesting that the complex is more strongly bound than a simple van der Waals complex. Infrared harmonic frequencies and intensites are also calculated at the RHF level. The infrared spectrum exhibits the normal effects of hydrogen-bond formation, increased intensity in the proton-donor mode, and little change in the electron-donor spectrum.