We have constructed a beam-laser lifetime-measuring apparatus and tested it by measuring the well known lifetime of the v=0 level of the $^{2}\mathrm{\ensuremath{\Sigma}}_{\mathrm{u}}^{+}$ state of $^{14}\mathrm{N}_{2}^{+}$. Our result of 61.8(5) ns is in excellent agreement with previous high-precision measurements. Employing this technique we performed measurements of the lifetimes of the four lowest vibrational levels of the B $^{2}\mathrm{\ensuremath{\Sigma}}^{+}$ state of $^{28}\mathrm{Si}^{16}$${\mathrm{O}}^{+}$. The results are (in ns) 69.5(6), 72.4(5), 75.2(5), and 78.0(8) for v=0, 1, 2, and 2, respectively.

SiO{sup +} is believed to play an important role in the silicon chemistry of interstellar clouds, and has been considered as a possible source of an unidentified observed line at 86.2 GHz. We have observed nearly 2000 lines in seven bands of the {triangle}v = 0 and {triangle}v = 1 sequences of the B{sup 2}{Epsilon}{sup +}-{Chi}{sup 2}{Epsilon}{sup +} system of SiO{sup +} using the combined techniques of laser-induced fluorescence and velocity modulation on a fast ion beam. Five of these bands have never been reported before. Analysis of the (0,0) and (1,1) bands is compared with earlier work, and the {Chi}-state v{double_prime} = 0 rotational constants are used to predict the frequencies of microwave rotational transitions of astrophysical interest. Anomalous rotational fine structure in the {Chi}-state v{double_prime} = 2 level and irregularities in high-lying rotational states of v{double_prime} = 0,1 are interpreted in terms of perturbations from the A{sup 2}{product} state, which lies very close to the {Chi} state.

We have applied fast-ion-beam laser spectroscopy to observe the 1s2s{sup 3}S {yields} 1s2p{sup 3}P transitions in Be III with complete resolution of the fine and hyperfine structure (I = 3/2). Using intracavity cw frequency-doubling in a Ti:Sapph laser, we produced {approximately}50 mW at {approximately}372.5 nm, continuously tunable over 60 GHz. A re-designed high-temperature ion source gave {approximately}50 nA of {sup 9}Be{sup 2+} at 16 keV, an order of magnitude improvement over an earlier version. Although the {approximately}10 nA laser-induced-fluorescence signals could be observed directly despite {approximately}45 nA due to scattered laser light, lock-in detection was used to obtain zero average background. The absolute wavelength reference was the Aime Cotton I{sub 2} Atlas, using linear absorption of the fundamental (745 nm). Results will be compared with theory and discussed with reference to systematic discrepancies of the 3P{sub 0} level which have been observed over a wide range of Z.