While most organic molecules with more than 4 atoms have multiple conformers as local minima, generating accurate ensembles requires a combination of both efficient sampling and accurate potential energy surfaces. We have recently benchmarked over 700 "typical" organic molecules using standard, classical molecular force fields, approximate semiempirical methods, and density functional theory. Rankings and correlations between low-level methods are amazingly poor. Discussion will focus on new methods to both sample the multi-dimensional problem and the potential to efficiently provide energy evaluations.
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