����������� 1.� Monte Carlo simulated annealing strategies, carried out on four different potential energy surfaces, were applied to benzene-cyclohexane clusters, BC_n, n = 3-7, 12 to identify low-energy isomers and to trace the evolution of structures as a function of cluster size.� Initial structures were first heated to ensure randomization and subsequent annealing yields optimized rigid, low-energy clusters.� Five major structural isomers are identified for BC₃:� one assumes the form of a symmetric, modified sandwich; the remaining four lack general symmetry, assuming distorted tetrahedral arrangements.� For BC₄ and larger clusters, the number of low-temperature isomers is large.� It is, nevertheless, feasible to classify isomers into Groups based on structural similarities.� The evolution of BC_n structures as a function of cluster size is observed to follow one of two primary paths:� the first maximizes benzene-cyclohexane interactions and places benzene in or near the BC_n cluster center; the competing path maximizes cyclohexane-cyclohexane interactions and distances benzene from the cluster's center of mass.� Results for BC₃ and BC₄, analyzed with reference to experimental results and models previously applied to interpret benzene-argon cluster spectra, suggest that the additivity model will need to be modified and extended to account for nonpolar solutes that are neither compact nor spherical.

����������� 2.� Neat fluorobenzene, (H₆H₅F)_n, and mixed fluorobenzene-benzene, (C₆H₆)_m(C₆H₅F)_n, clusters were examined via resonant two-photon ionization (R2PI) spectroscopy through fluorobenzene's B₂ ← A₁ 0⁰₀ transition.� The fluorobenzene molecule's R2PI spectrum was analyzed� with reference to an MP2/6-31+(2d,p) ground state frequency calculation.� The ultraviolet cluster spectra contain no unique sharp features, indicating the presence of many isomers for all cluster sizes.� Ongoing analysis focuses on determining the cluster size evolution of three broader features ubiquitous through the spectra.� These features may hold the key to assigning structural types and the evolution of their relative populations as a function of size.

����������� 3.� Carbon, hydrogen, and 2D NMR spectra were obtained for the 1,2,3 � alternate dibenzyl bis-teo (alt) and the cone � dibenzyl bis-teo (cone) calixarene structures.� Although many of the NMR peaks had been previously assigned, some such assignments remained ambiguous.� Theoretical NMR shifts and Mulliken charges were calculated via Gaussian 03W software.� Optimized structures, charge distributions, and ground state energies were calculated using the B3LYP/6-31G(d) method/basis set.� Proton and carbon NMR spectra were calculated based on optimized structures, using the HF/6-31G(d) method/basis set.� Calculations were carried out for both isomers, first in the gas phase�with and without imposed symmetry, and �then in solution with a chloroform solvent.� Results indicate that imposed symmetry leads to higher optimized energies:� thus, the molecules prefer forms slightly distorted from high symmetry structures.� In contrast, imposed symmetry does not noticeably affect predicted NMR shifts:� shifts of non-symmetrized forms�averaged over positional-equivalent atoms�do not differ systematically from corresponding shifts calculated for fully symmetrized forms.� Analysis is underway to correlate Mulliken charges to steric compression, as observed in the NMR data.