The development of accurate and broadly applicable methods for large molecules continues to be a major challenge in quantum chemistry. We have developed several new cutting-edge fragment-based methods for the accurate evaluation of the energies of large molecules [Molecules-In-Molecules (MIM),1 Many-Overlapping-Boby (MOB),2 Dimers-Of-Dimers (DOD),3 and Grid-Adapted-Manybody-Analysis (GAMA)4]. In this presentation, I will provide a brief overview of the methods developed in our group that focuses on estimating accurate energies of large systems including both bonded (e.g. peptide) and nonbonded (e.g. water clusters) systems. In all these methods, we use a multilayer partitioning technique with multiple levels of theory using a generalized hybrid energy expression, similar in spirit to the ONIOM methodology. Our methods have excellent scaling as well as high accuracy and are useful tools for investigations on large molecular systems. This presentation will include analysis of several different fragmentation strategies5 as well as careful assessments from applications on peptides and large water clusters. 1. Mayhall, N. J. and Raghavachari, K. J. Chem. Theory Comp. 2011, 7, 1336. 2. N. J. Mayhall and K. Raghavachari, J. Chem. Theory Comput. 2012, 8, 2669. 3. Saha, A. and Raghavachari, K., J. Chem. Theory Comput., 2014, 10, 58. 4. Saha. A. and Raghavachari, K. (in preparation). 5. Saha. A. and Raghavachari, K. Chem. Rev. 2015, 115, 5643.

Accurate, fragment-based quantum chemistry methods for large molecular systems

251st National Meeting (2016)

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