Seminars & Events

LCF Seminar
"Effective Fragment Potential method for electronic excited states: Theory, applications, and benchmarks"

DATE: August 17, 2011
TIME: 2:00 PM - 3:00 PM
SPEAKER: Lyudmila V. Slipchenko, Department of Chemistry, Purdue University
LOCATION: Building 240 Conference Room 4301, Argonne National Laboratory
HOST: Yury Alekseev

Description:
Differential solvation of the electronic states of a chromophore in a solvent, called solvatochromism, can be used as a measure of solute-solvent interactions. Since electronic states of organic chromophores in non-polar solvents and in a protein environment are typically well localized within the solute, it allows one to separate a system and use hybrid QM/MM (quantum mechanics / molecular mechanics) approach. We developed a series of QM/MM methods for description of the electronic excited states in the environment. The equation-of-motion coupled cluster with single and double excitations (EOM-CCSD) configuration interaction singles with perturbative doubles (CIS(D)) methods and time-dependent density functional theory (TD-DFT) are used to describe the QM region. The effective fragment potential (EFP) method describes the MM part. The EFP method overcomes the most significant limitations of QM/MM by replacing empirical MM interactions and QM-MM coupling by parameter-free first principles based ones, while retaining the computational efficiency of QM/MM. We will discuss accuracy of EFP and details of implementation of the QM/EFP schemes, as well as applications to solvatochromic shifts of organic chromophores in various solvents.

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