Optimization at the UM06/6-311g++(2d,p) level yielded geometries for GBL, GHBA, Water, and GBL*water complexes. It was found that the most stable complex was Carbonyl Oxygen, α Left Two. It is thought this stability is due to having two hydrogen bonds, both having intermediate donor to acceptor bond angles. Considering primary and secondary hydrogen bonds were found among multiple complexes, multiple hydrogen bonds seem to be necessary to confer further stability, rather than one strong hydrogen bond, which was seen in less stable complexes. IR spectra obtained for the complexes showed a good indication for stable hydrogen bond formation in GBL was a red-shift at the C=O and γ C-O stretches, and a blue-shift at the H-O-H bend of water in the 1600 cm-1 region. Transition state geometries were found for the hydrolysis of GBL*water to GHBA in addition to transition state geometries between each of the complexes. This allowed for a proposed reaction pathway from the most stable complex to a complex that resembles the transition state of the hydrolysis reaction through an intermediate complex. Isotopic substitution was found to have the same effect in all of the complexes while singlet electronic transitions with the highest oscillator strength were seen in the 201 nm to 208 nm range. This study was meant to lay a foundation for further understanding of GBL*water complexes and the breadth of its findings may be useful in future experimentation including matrix isolation IR in solid inert gases, isotopic substitution studies, photodecomposition analysis, and inducing the hydrolysis reaction via irradiation
