FREQUENCY-DEPENDENCE OF THE POLARIZABILITY DERIVATIVE [PARTIAL-DERIVATIVE-ALPHA(OMEGA) PARTIAL-DERIVATIVE-R](0) OF CHLORINE FROM TEMPERATURE-DEPENDENT GAS-PHASE REFRACTIVE-INDEX MEASUREMENTS/

The refractive index n(omega, T, p) of molecular chlorine, Cl-2, was m easured in the ranges of temperature T between 290 and 1100 K and pres sure p between 10(4) and 2 x 10(5) Pa and at three wavelengths lambda = 2 pi c(0)/omega between 632.990 and 543.516 nm. From these measureme nts the frequency and temperature dependence of the mean dipole polari zability <alpha(omega)>(T) of Cl-2 was obtained. The polarizabilities were analysed according to theories of Bell and Buckingham, yielding 1 0(20)[partial derivative alpha(omega)/partial derivative r](0)/m(2) = 2.02(22) + 6.27(51) x 10(-32) (omega/s(-1))(2) for the frequency depen dence of the polarizability derivative of chlorine between omega = 0 a nd 3.5 x 10(15) s(-1). This result is in fair agreement with ab initio calculations, but disagrees with polarizability derivatives obtained from measurements of the differential Raman scattering cross-section.