Optical properties of rare-gas fluoride dimers and trimers dissolved in liquid rare gases

Abstract

Cryogenic rare-gas fluorine solutions are studied with optical excitation provided by excimer laser radiation at 193, 248, and 351 nm. Fluorescences corresponding to dimer [$\mathrm{Kr}{\mathrm{F}}^{*}(D\frac{1}{2}\ensuremath{\rightarrow}X\frac{1}{2})$, $\mathrm{Xe}{\mathrm{F}}^{*}(D\frac{1}{2}\ensuremath{\rightarrow}X\frac{1}{2})$, $\mathrm{Xe}{\mathrm{F}}^{*}(B\frac{1}{2}\ensuremath{\rightarrow}X\frac{1}{2})$, $\mathrm{Xe}{\mathrm{F}}^{*}(C\frac{3}{2}\ensuremath{\rightarrow}A\frac{3}{2})$] and trimer (${\mathrm{Ar}}_{2}$${\mathrm{F}}^{*}$, ${\mathrm{Kr}}_{2}$${\mathrm{F}}^{*}$, ${\mathrm{Xe}}_{2}$${\mathrm{F}}^{*}$) transitions are detected in several rare-gas liquid hosts. All of the emission bands detected exhibit red shifts with respect to the gas-phase spectra. With the exception of the $\mathrm{Xe}{\mathrm{F}}^{*}(C\ensuremath{\rightarrow}A)$, ${\mathrm{Kr}}_{2}$${\mathrm{F}}^{*}$, and ${\mathrm{Xe}}_{2}$${\mathrm{F}}^{*}$ bands, the shifts increase in magnitude with an increase of the atomic number of the host.