Method for the Determination of Oxygen in FLiBe via Inert Gas Fusion.

In nuclear reactors that use molten fluoride salts, either as coolants or as the medium for the fuel, the purity of the salts is critical for controlling salt chemistry and mitigating corrosion. Water is a particularly important contaminant in this regard, as it participates in a number of important corrosion reactions, so the careful measurement of oxygen, which is principally present in the salts due to water contamination, is a critical step in salt characterization. Here, we present an analytical method for quantifying oxygen contamination in LiBeF (FLiBe), a technologically important and suitably representative fluoride salt, with a detection limit of 22 μg of oxygen, or 110 ppm in a 200 mg sample.

Phase correlation during two-photon resonance process in an active cavity.

In this paper, we experimentally demonstrate a strong correlation between the frequencies of the Raman pump and the Raman probe inside an optically pumped Raman laser. We show that the correlation is due to rapid adjustment of the phase of the dipoles that produce the Raman gain, following a sudden jump in the phase of the Raman pump. A detailed numerical model validates this interpretation of the phase correlation.

Optical cooling in Er3+:KPb2Cl5.

For the first time, optical cooling has been observed in the (4)I(13/2) excited state of erbium(III), using the low phonon energy host materal, potassium lead chloride (KPb(2)Cl(2)). Cooling was observed when samples were pumped at wavelengths longer than 1557 nm, 17 nm longer than the mean fluorescence wavelength of 1540 nm, which implies a nonradiative heat load of 1.1% for the (4)I(13/2)-->(4)I(15/2) transition.

Doubly vibrationally enhanced four-wave mixing in crotononitrile.

Doubly vibrationally enhanced (DOVE) resonances have been observed in the infrared four-wave mixing (IRFWM) spectra of crotononitrile. The 2D DOVE-FWM spectra of the cis and trans isomers of crotononitrile showed cross peaks between the CN stretching fundamental and the CN + C=C stretch and the CN + C-C stretch combination bands for each of the two isomers that were observed, demonstrating the isomer selectivity of DOVE-IRFWM. Frequency-domain simulations were able to reproduce the features of the observed spectra, so the values for the nonlinearity and dephasing rates of all of the nonlinear processes could be measured.