Green Plant Photosynthesis

We have been investigating the theory of exciton-phonon interaction in a molecular crystal and numerically simulating the exciton dynamics on thylakoid membrane. This has led to the estimation of the NADPH production rate in chloroplast in a fairly narrow range. The latter rate can be used to solve the kinetics of the dark cycle of reactions and determine the temperature dependence of glucose production rate in green plants. So far, we have been successful in deriving a rate expression for CO2 assimilation that agrees with the observed rate for different types of C4 plants.
We also work on the quantum chemical determination of the absolute free energy of redox reactions involved in the so-called Z scheme and the corresponding rate of electron transfer. This line of work explains the redox behavior of species in thylakoid and generates some idea about the environment within the membrane, besides confirming the validity of the Z scheme on a theoretical basis.

Magnetism in Chemistry

Quantum chemical calculations are carried out to determine the nature of intra-molecular and inter-molecular magnetic interactions and estimate the corresponding exchange coupling constant. The formation of a ferromagnetic solid, however, depends on the crystal structure. We also explore magnon-based theoretical treatments for ferromagnetic and anti-ferromagnetic molecular crystals.
We have been involved in deriving the correct Hamiltonian operators for atoms and molecules in a strong magnetic field. The treatment is necessarily relativistic in nature. We use interactions from quantum electrodynamics. So far, we have prepared Hamiltonians for atomic systems. These operators can be used in quantum mechanical calculations on atomic systems in strong field. They reduce to the traditionally known Hamiltonians and some correction terms in the so-called non-relativistic limit and for a weak field.

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