No abstract

Doppler-limited tunable diode laser spectra of v. of 28SiF. have been analyzed and the spectroscopic constants determined. In contrast to most earlier low-resolution studies, the Coriolis constant t •. when combined with t 3 as obtained from previous laser spectroscopy. yields a zeta sum that is within 5% of the expected harmonic value of 1/2. The band origins of 12 overtones and combinations have been obtained from Fourier-transform spectra (0.04 cm-1 resolution). resulting in estimates of the anharmonicity constants and harmonic frequencies. From the Coriolis constants and the isotope shifts in v 3 we have redetermined the general quadratic force field of SiF 4 ,

No abstract

The crystal structure of K2VO2F3 has been determined by a three-dimensional single-crystal X-ray diffractometer study. The crystals are orthorhombic, space group Pnma, with a = 7.379 (4), b = 5-640 (2), c= 11.413 (7). For Z=4, De= 3.05 g.cm-3, in agreement with the measured density, Din= 3.05 g.cm-a. The structure was refined by full-matrix least squares to a weighted R' (the conventional R factor was 0-0258) value of 0.0198 for 668 observed reflections. Octahedrally coordinated vanadium atoms are

The absorption spectra of fluoride salts of 5f3Np4+ obtained at room temperature in various environments were compared with the known spectra of f3Nd3+ and U3+. Correlation with known spectra allowed assignment of levels to Np4+, and based on these, the complete 41-level f3 intermediate spin–orbit coupling diagram was constructed. The diagram was used to interpret the absorption spectra and to make spectroscopic assignments to 12 low-lying electronic energy levels for Pu5+. Ten low-lying levels for Am(VI) obtained from published AmO2++ aqueous solution spectra were interpreted also. Spectroscopic parameters obtained from least-squares fits to the observed spectra were: Np4+, F2 = 232.4 cm−1, ζ = 2178 cm−1; Pu5+, F2 = 230.5 cm−1, ζ = 2295 cm−1; AmO2++, F2 = 260.3 cm−1, ζ = 3070 cm−1. Only the lowest-lying energy levels were found to be in substantial agreement with the f3 intermediate coupling diagram.