ABSTRACT OF THE TALK
I will review our theoretical studies of the intricate quantum translation-rotation (TR) dynamics of H2 and H2O molecules inside the fullerene C60. The salient feature of the TR energy level structure of both H2@C60 and H2O@C60, revealed by the calculations, is the clustering of the TR eigenstates into closely spaced multiplets. It arises from the vectorial coupling of the orbital angular momentum associated with the center-of-mass motion of the guest molecule and its rotational angular momentum, caused by the highly symmetric (Ih) confining potential of the C60 cage, to give the new total angular momentum. The predicted distinct spectroscopic signatures of this TR coupling were later observed in the infrared and inelastic neutron scattering (INS) spectra of H2 in C60. We have also developed the methodology for accurate quantum simulations of the INS spectra of a diatomic molecule inside a nanocavity of an arbitrary shape, and used in the calculations aiming to unambiguously assign the experimental INS spectra of H2 and HD inside C60. This work ultimately led to the discovery of the first ever selection rule in the INS spectroscopy of discrete molecular compounds, confirmed by the INS study of H2 in C60. Time permitting, insights from our recent calculations of the TR eigenstates of dipole-coupled H2O@C60 assemblies will be discussed.
BIOGRAPHY OF THE SPEAKER
Zlatko Bačić is a Professor at the Department of Chemistry, New York University, in New York, USA, and an Affiliated Professor at the NYU-ECNU Center for Computational Chemistry at NYU Shanghai. He received his B.S. degree in Chemistry from the University of Zagreb, Croatia, in 1977, and Ph.D. in theoretical chemistry at the University of Utah, Salt Lake City, USA, in 1981. He was a postdoctoral fellow at the MPI für Strömungsforschung in Göttingen, Hebrew University of Jerusalem, The University of Chicago, and Los Alamos National Laboratory. In 1988, he joined the faculty of the NYU Chemistry Department. In recent years, his group has pioneered rigorous investigations of the quantum dynamics and INS spectroscopy of the coupled TR excitations of H2, H2O, and CH4 molecules inside the nanocavities of fullerenes, clathrate hydrates, and metal-organic frameworks. In recognition of his significant contributions to theoretical chemistry, Professor Bačić was elected a Fellow of the American Association for the Advancement of Science in 2011, and a Fellow of the American Physical Society in 2009. In 2013-2014, he held the Lady Davis Visiting Professorship at Technion-Israel Institute of Technology in Haifa, and the Joseph Meyerhoff Visiting Professorship at the Weizmann Institute of Science in Rehovot, Israel.