| Fourier transform microwave spectroscopy has been used to study a number of reactive systems, with the primary goal of probing the effects of solvent on a molecule or a weakly bound acid-base system at the small cluster level. Because these systems are particularly sensitive to their first, nearest neighbors, the studies focus on examining structural changes and electronic rearrangement that occurs with the addition of a single solvent molecule, or microsolvent.; The structural effects of microsolvation were examined on two prototypical acid-base systems. The first sought to ascertain the effect of microsolvent polarity by microsolvating HCN-SO3 with Ar and CO, forming the complexes HCN-SO3···Ar and HCN-SO 3···CO. Dipole moments and ab initio calculations also are reported. The second examined the effect of microsolvation on the primary hydrogen bond distance of (CH3)3N···HF, by adding a single HF molecule, forming the complex (CH3) 3N···HF···HF. The Stark effect was measured on a series of hydrogen halide complexes. These systems are prototypical complexes with which to study proton transfer across a hydrogen bond. The resulting dipole moments are discussed in terms of the degree of proton transfer. The dipole moment also was determined for the H2SO4···H 2O complex, which provides an important model system for understanding rates of binary homogeneous nucleation, and a series of ab initio calculations were performed in support of the results.; Finally, the microwave spectrum of the radical complex OH-H2O was observed and analyzed using a two-state model which accounts for nuclear motion on the 2A' and 2A" potential surfaces. The results provide insights into the effects of the partial quenching of orbital angular momentum. |
