T. Nagata

Nonlinear electrooptical spectroscopy of ferroelectric liquid crystals

Abstract We have studied the nonlinear electrooptical relaxation spectra of the Goldstone mode in a ferroelectric liquid crystal (FLC). The linear spectrum experimentally obtained shows a single relaxation of Debye type and the second and third-order nonlinear spectra show an extended form of Debye type to a nonlinear case. We have also studied the electrooptical response theoretically by means of a simple torque balance equation describing the dynamics of the Goldstone mode. The calculated nonlinear spectra are found to be in a rather good agreement with experimentally obtained ones.

Photo- and collision-induced dissociation of Ar cluster ions

Photo- and collision- induced dissociation of an argon cluster ion, Arn+, were investigated by use of mass spectrometry. The kinetic and angular distributions of the ionic and neutral photofragments revealed two reaction pathways; dissociation of the trimeric core ion and evaporation from its solvation shell. In the Kr and Ne collisions with Arn+, the size- and collision energy- dependences of the dissociation cross sections were explained in the scheme of the charge - induced dipole, and induced dipole - induced dipole scatterings. Conversion efficiency of the collision energy into the internal energy of Arn+ was found to be proportional to the internal degrees of freedom. The upper limit of the conversion efficiency was estimated to be about 60 % in the collision energy of 0.2 eV.