Theoretical study on the origin of blue-shift of hydrogen bonding frequency in acetonitrile - water and benzonitrile - water clusters

초록

We investigated acetonitrile - (water)n clusters to study their spectroscopic properties, especially the blue-shift of the infrared frequency, as functions of the number of binding water molecules. We found that the structure of hydrogen bonding (pi- or sigma-type) induce the CN stretching frequency to shift in opposite directions. We report theoretical attempts to unveil the origin of this interesting phenomenon by carrying out ab initio calculations. We also describe calculations for the substituted benzonitrile-(water)n clusters, concluding that electronic effects are not the major factor for the blue-shifting.