Justification and Scope : Hybrid quantum mechanical / molecular mechanical (QM/MM) methods have been developed extensively over the last few decades starting with the seminal works by Warshel, Levitt and Karplus. These methods have mostly been applicable to biological systems in ground state, specifically for enzyme catalysis. However, environment effects can be quite considerable when dealing with excited state phenomena and photoprocesses. Photon assisted processes are common in biological systems such as light harvesting complexes, fluorescent proteins and photocatalytic centers, as well as in abundance of photovoltaic materials.

While the importance of understanding, predicting and eventually controlling the environment effects on excited state processes are unequivocal, computational modeling of these effects is challenging. One of the major difficulties is describing various non-covalent interactions in a balanced manner. It is further important to be able to not only predict, but give physical interpretations to the non-covalent interactions. Furthermore, the excited state methods as developed within the electronic structure community are not always conducive to interfacing with available MM force fields and therefore, need to be suitably modified. Thus, the main challenge is development of QM and MM methodology and software in accord with each other, to make QM and MM models compatible with each other while retaining the computational accuracy and speed. This meeting proposes to bring in discussions about recent developments in the field of hybrid QM/MM models for electronic excited states and will encompass the following topics:
-Polarizable comtinuum models
-Polarizable embedding
-Linear response approximation
-Effective Fragment potential
-Many body expansion
-Dynamical mean field theory
-Other embedding methods