Born December 17, 1946 in Naihati, West Bengal, India.
Professor, Department of Physical Chemistry and Director, Indian Association for the Cultivation of Science, Kolkata, India.
Asutosh Mukherjee Prize (1965); Shantiswarup Bhatnagar Prize (1987); Jagdish Shankar Endowment Lecture of Indian National Science Academy (1994). Fellow: Indian Academy of Science (1987), Indian National Science Academy (1991). Foundation Fellow: West Bengal Academy of Science and Technology (1988). Life Member of the Indian Association for the Cultivation of Science (1997), Silver Medal of he Chemical Research of India (1999).
More than 150 papers and monographs on various aspects of Theoretical Chemistry. Editor of two volumes:
Aspects of Many-Body Effects in Molecules and Extended Systems, Lecture Notes in Chemistry, Vol. 50 (Springer Verlag, 1989);
Applied Many-Body Methods in Spectroscopy and Electronic Structure (Plenum Press, 1992).
Electronic Structure: One of the earliest proponents of the multi-reference coupled cluster theory. Introduced the concept of the Valence Universality in this context. The first proponent of the multi-reference many-body theories for general model spaces. One of the earliest developers of the coupled cluster based linear response theory for energy differences of spectroscopic interest.
General Methodology in Many-Body Theory: Formulated field-theories based on the notion of extended normal ordering for general expectation values, covering correlated reference states, thermal traces and stochastic averages. Methods for direct determination of cumulants of the reduced density matrices.
Real- and Imaginary-time Quantum Dynamics: Developed a general non-perturbative operator cumulant expansion for real- and imaginary-time quantum dynamics. The formulation yields in the imaginary time-domain the finite-temperature version of the multi-reference dynamical coupled cluster theory.