R. C. Hanson

Mercury detection by means of thin gold films

The adsorption of elemental mercury vapor on a thin (several hundred angstroms) gold film produces resistance changes in the film. An instrument for the detection of mercury based on this phenomenon is simple and rapid and requires no chemical separations other than passage of the vapor sample through a few standard dry filters. The instrument is portable, and the technique is directly applicable to environmental problems and geochemical prospecting. The limit of detection of the prototype instrument is 0.05 nanogram of mercury.

Brillouin scattering study of methanol at high pressure

Abstract Brillouin scattering has been used to study methanol as a function of pressure up to 8.4 GPa. Our near-forward-scattering experiments yield the pressure dependence of the velocity of longitudinal acoustic (LA) phonons, while we determine the pressure dependence of the product of the index of refraction and the LA phonon velocity from our backscattering experiments. The pressure dependence of the LA phonon lifetimes is obtained from the linewidth of the measured Brillouin peaks. From our backscattering experiments we find that the normalized phonon attenuation is a decreasing function of pressure.

Raman spectra and phase diagram of fluorine at pressures up to 6 GPa and temperatures between 10 and 320 K

The Raman spectra and phase diagram of fluorine were studied in a diamond‐anvil cell up to 6 GPa over the temperature range 10–300 K. The sample slowly reacted with the diamond anvils to form CF4. The vibron frequencies in α‐F2 and β‐F2, as well as the lattice modes in α‐F2, were determined as a function of pressure. No new phases were discovered. The α–β phase boundary can be fit with an equation of the Simon form: Pαβ (GPa)=−0.385(10) +4.80(9)×10−4 Tαβ1.75 (K). The melting curve was established to lie between limiting curves: Puppermelt (GPa)=−0.107+1.01×10−4T1.75melt (K) and Plowermelt (GPa)=−0.140+1.32×10−4 T1.75melt (K).