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81.
C. Linton 《Journal of Molecular Spectroscopy》1980,79(1):90-100
Spectra of GeS have been obtained in a chemiluminescent flame produced by the reaction Ge + OCS → GeS + CO. Neither of the known band systems, D1Π-X1Σ+ and E1Σ+-X1Σ+, was observed, but two new band systems in the regions 350–400 and 420–650 nm were obtained. By comparison with similar systems in isovalent molecules, these were assigned as b3Π1-X1Σ+ and a3Σ+-X1Σ+, respectively. Vibrational assignments were made with the help of the germanium isotope effect and vibrational constants were obtained for the states involved. Approximate Morse potential Franck-Condon factors were computed and were shown to fit the general trend of the intensity distribution for both systems. Addition of active nitrogen to the flame was shown to increase the intensity of the b-X system by an order of magnitude while hardly affecting the a-X system. Constants (in cm?1) obtained for the two new states are: a3Σ+: Te = 21986.3 ± 2.3, ωe = 388.9 ± 1.0, ωexe = 1.35 ± 0.11; b3Π1: Te = 27192.0 ± 1.8, ωe = 435.4 ± 1.1, ωexe = 1.68 ± 0.20. 相似文献
82.
G.R. Hébert R.W. Nicholls C. Linton 《Journal of Quantitative Spectroscopy & Radiative Transfer》1980,23(2):229-235
The relative intensity measurements of Linton and Nicholls1 on the AlO blue-green system have been placed on an absolute scale using the radiative lifetimes of Johnson et al.2 and Dagdigian et al.3 for levels of the B2Σ state of AlO. Absolute values of Einstein A coefficients, band strenghts and band oscillator strengths are presented for 75 bands of the system. 相似文献
83.
Bashall A Doyle EL García F Lawson GT Linton DJ Moncrieff D McPartlin M Woods AD Wright DS 《Chemistry (Weinheim an der Bergstrasse, Germany)》2002,8(24):5723-5731
The reaction of the dimeric phospha(III)zane [ClP(mu-Npy)]2 (1) (py = 2-pyridyl) with pyNHLi (2:1 equivalents, respectively) in THF/Et3N leads to rapid formation of the bicyclic nona-phospha(III)zane [[ClP(Npy)2]2-[P2(Npy)]] (2). This novel rearrangement can be rationalised by a mechanism involving "twisting (or swivelling)" of the central P(mu-Npy)P fragment of the presumed intermediate [[ClP(mu-Npy)2P]2(mu-Npy)] (3), a process that provides a fundamental mechanistic relationship between the majority of previously reported imidophosphospha(III)zanes. This process is fundamentally reliant on relief from ring strain on going from the four-membered ring units of 3 to the six-membered units of 2. The rearrangement observed for 1 is suppressed on steric grounds by Me-substitution of the pyridine ring at the 6-position, the dimeric phosphazane [ClP(mu-N-6-Me-py)]2 (4) (6-Me-py = 6-methyl-2-pyridyl) being formed almost exclusively in the 1:1 reaction of PCl3 with 6-Me-pyNHLi. The syntheses and X-ray structures of 1, 2 and 4 are reported, together with 31P NMR spectroscopic and DFT calculational studies of the conversion of models of 1 into 2. The combined studies pinpoint relief from ring strain as the key factor dictating the rearrangement. 相似文献
84.
Minor impurities in the antibacterial agent temafloxacin hydrochloride were determined using high-performance liquid chromatography. Manufacturing impurities and degradation products were separated using a reversed-phase system with gradient elution. Detector response was linear for the individual impurities to approximately 50 micrograms/ml which represents 2.5% of the drug concentration. The procedure provides quantitation of impurities to approximately the 0.05% level with precision (relative standard deviations) of 4.7% to 29% in typical bulk drug lots. A variety of reversed-phase columns were evaluated for the assay method with optimum resolution achieved using a 5-microns Nucleosil C18 packing. 相似文献
85.
A study has been made of emission spectra of TiO in chemiluminescent flames produced by reactions of titanium atoms with O2, N2O, NO2, NO, and CO2. Examination of the differences in intensity distributions of the Ti + N2O and Ti + O2 flames supports a recent experiment placing the a1Δ state at about 3500 cm?1 above the X3Δ ground state (1). An infrared system at 843.2 nm has been assigned as the ?(E3Π-X3Δ) system, which previously has been seen in an inert gas matrix (2). E3Π state constants (in cm?1) obtained from measured gas-phase bandheads were found to be Addition of active nitrogen to the flames was found to cause considerable enhancement of TiO emission. 相似文献
86.
87.
The A2Π–X2Σ+ transition of 174Yb35Cl and 172Yb35Cl has been rotationally analyzed for the first time. Doppler-limited laser excitation spectroscopy with selective detection of fluorescence was used to obtain spectra of the 0–0 and 1–0 bands with a measurement accuracy of approximately 0.0035 cm−1. Resolved fluorescence was used to record the 0–1, 0–2, and 0–3 bands and to unequivocally assign the rotational numbering, N, to the laser excitation spectra. In total, over 1300 line positions have been measured and assigned for each of the two isotopomers and employed in least-squares fits of molecular parameters. The principal results for the A2Π state are Ae = 1491.494(2) cm−1 and Re = 2.4433(1) Å, and for the X2Σ+ state, Re = 2.4883(2) Å and γe = 4.59(2) × 10−3 cm−1. The interaction between the X2Σ+ and A2Π states has been investigated and is shown to be the main contributor to the spin–rotation splitting in the ground state. 相似文献
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