Application of time-dependent density functional theory to optical activity

As part of a general study of the time-dependent local density approximation (TDLDA), we here report calculations of optical activity of chiral molecules. The theory automatically satisfies sum rules and the Kramers-Kronig relation between circular dichroism and optical rotatory power. We find that the theory describes the measured circular dichroism of the lowest states in methyloxirane with an accuracy of about a factor of two. In the chiral fullerene C_76 the TDLDA provides a consistent description of the optical absorption spectrum, the circular dichroism spectrum, and the optical rotatory power, except for an overall shift of the theoretical spectrum.Comment: 17 pages and 13 PostScript figure

Nuclear Clusters as a Probe for Expansion Flow in Heavy Ion Reactions at 10-15AGeV

A phase space coalescence description based on the Wigner-function method for cluster formation in relativistic nucleus-nucleus collisions is presented. The momentum distributions of nuclear clusters d,t and He are predicted for central Au(11.6AGeV)Au and Si(14.6AGeV)Si reactions in the framework of the RQMD transport approach. Transverse expansion leads to a strong shoulder-arm shape and different inverse slope parameters in the transverse spectra of nuclear clusters deviating markedly from thermal distributions. A clear ``bounce-off'' event shape is seen: the averaged transverse flow velocities in the reaction plane are for clusters larger than for protons. The cluster yields --particularly at low $p_t$ at midrapidities-- and the in-plane (anti)flow of clusters and pions change if suitably strong baryon potential interactions are included. This allows to study the transient pressure at high density via the event shape analysis of nucleons, nucleon clusters and other hadrons.Comment: 38 pages, 9 figures, LaTeX type, eps used, subm. to Phys. Rev.

VIBRONIC MAGNETIC ROTATIONAL STRENGTHS IN THE 1B2u^{1}B_{2u} STATE OF BENZENE

Author Institution: Department of Chemistry, Laboratory of Chemical Physics University of Minnesota Institute of Arthritis; Department of Chemistry, Stanford UniversityProgressions of B terms in the magnetic circular dichroism (MCD) spectrum of the vibronical1y allowed 260 nm $^{1}A_{1g} \rightarrow ^{1}B_{2u}$ transition of benzene are assigned to $e_{2}$ g vibrationa1 modes. Experimental MCD spectra of benzene and benzene- $d_{6}$ in solution at room temperature and liquid nitrogen temperature are reported. Magnetic rotational strengths (B values) and oscillator strengths associated with each of the four e2g vibrations in benzene and benzene-$d_{6}$ have been calculated by two different methods, a perturbation treatment Involving the $\pi$ electrons only and a CNDO/S-CI calculation for a geometry in which the nuclei are distorted along a normal coordinate. The results of the two calculations agree reasonably well with each other and with experiment. Two terms that dominate the magnetic rotational strengths are identified

ANHARMONIC EFFECTS IN VIBRATIONAL CIRCULAR DICHROISM

Author Institution: Department of Chemistry, University of MinnesotaA formalism has been developed for the treatment of vibrational circular dichroism using first-order anharmonic wave functions. Expressions have been developed for the optical activity of binary overtone and combination transitions. The theory has been applied to the chiral molecule HCBrClF