LOW-FREQUENCY ELASTIC RESPONSE OF A SPHERICAL-PARTICLE

A continuum approach is discussed to describe the low-frequency respon se of a small spherical particle under laser irradiation. This respons e is interpreted in terms of essentially long-wavelength normal vibrat ions of a perfectly elastic globe. The eigenfrequencies of spheroidal and torsional oscillations are derived as functions of the particle ra dius R and multipole degree 1. The frequencies of spheroidal vibration s are found to be omega(s) = omega0 [2(21 + 1)(l - 1)]1/2; the eigenmo des of torsional oscillations are given by omega(t) = omega0 [(2l + 3) (l - 1)]1/2, with omega0(2) = mu/(rho0R2), where mu and rho0 are the s hear modulus and the bulk density, respectively. The obtained results may be tested on spherical clusters with R approximately 100-200 k, ir radiated by infrared laser light with the wavelength lambda approximat ely 5000 angstrom.