Molecular spectra, quantum chaos, and scars

Low resolution features in the spectra of classically chaotic atomic and molecular systems are known to be related to recurrences induced by classical periodic motions. In this paper we study how such characteristics reveal in the LiNC/LiCN isomerizing molecular system, and describe how the transition from regularity to classical chaos that takes place in this system shows up at quantum level in the structure of the corresponding wavefunctions in the form of "scars" . To this end we use some projection techniques, based on the propagation of wave packets, which have been developed in our laboratory. In this way some regions at the border of the chaotic region can be detected, in which the systematics of "scar" formation can be studied at a very elementary level, without complications due to the high level density which are customarily used in this type of studies in order to achieve the semiclassical limit