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101.
102.
103.
Infrared and microwave spectral measurements are given for three isotopically enriched species of carbonyl selenide. The high-resolution infrared measurements (made near 2000 and 2600 cm?1) provide constants for the following transitions: 10000000 for 16O12C80Se; 10000000 and 11100110 for 18O12C80Se; and 10000000, 11100110, 10010001, and 10010000 for 16O13C80Se. Microwave measurements are given for the J = 4 ← 3, and 3 ← 2 transitions of 18O12C80Se and 16O13C80Se in the 0000, 0110, 0200, 0220, and 0001 states. Equilibrium rotational constants are given for all three isotopic species and the equilibrium bond distances are determined to be and . 相似文献
104.
Steenwyk RC Hutzler JM Sams J Shen Z Siuzdak G 《Rapid communications in mass spectrometry : RCM》2006,20(24):3717-3722
The application of atmospheric pressure desorption/ionization on silicon (AP-DIOS) coupled with ion trap mass spectrometry (ITMS) was investigated for the quantification of midazolam in rat plasma, and determination of midazolam 1'-hydroxylation kinetics in pooled human liver microsomes. Results indicate good sensitivity with absolute detection limits for midazolam in rat plasma of approximately 300 femtograms. A linear dynamic range from approximately 10-5000 ng/mL was obtained in rat plasma with analysis times of 1 min per sample. Kinetic constants for midazolam 1'-hydroxylation in human liver microsomes yielded an apparent Km of 10.0 microM and Vmax of 6.4 nmol/min/mg. Studies investigating the inhibition of 1'-hydroxymidazolam formation by the cytochrome P450 3A4 model inhibitor ketoconazole yielded an IC50 of 0.03 microM. Quantitative precision for replicate analysis of rat plasma and human liver microsomal samples was variable with relative standard deviation (RSD) values ranging from a low of approximately 3% to over 50%, with the highest variability observed in data from human liver microsomal incubations. While preliminary studies investigating the application of AP-DIOS-ITMS suggested feasibility of this technique to typical pharmacokinetic applications, further work is required to understand the underlying causes for the high variability observed in these investigations. 相似文献
105.
Timothy J. Johnson Robert L. Sams Sarah D. Burton Thomas A. Blake 《Analytical and bioanalytical chemistry》2009,395(2):377-386
We report quantitative infrared spectra of vapor-phase hydrogen peroxide (H2O2) with all spectra pressure-broadened to atmospheric pressure. The data were generated by injecting a concentrated solution
(83%) of H2O2 into a gently heated disseminator and diluting it with pure N2 carrier gas. The water vapor lines were quantitatively subtracted from the resulting spectra to yield the spectrum of pure
H2O2. The results for the ν6 band strength (including hot bands) compare favorably with the results of Klee et al. (J Mol. Spectrosc. 195:154, 1999) as well as with the HITRAN values. The present results are 433 and 467 cm-2 atm−1 (±8 and ±3% as measured at 298 and 323 K, respectively, and reduced to 296 K) for the band strength, matching well the value
reported by Klee et al. (S = 467 cm−2 atm−1 at 296 K) for the integrated band. The ν1 + ν5 near-infrared band between 6,900 and 7,200 cm−1 has an integrated intensity S = 26.3 cm−2 atm−1, larger than previously reported values. Other infrared and near-infrared bands and their potential for atmospheric monitoring
are discussed. 相似文献
106.
M.A.H. Smith C.P. Rinsland R.L. Sams V. Malathy Devi 《Journal of Quantitative Spectroscopy & Radiative Transfer》2008,109(6):922-951
Half-width and pressure-induced shift coefficients; the temperature-dependence exponents of the half-widths and the temperature-dependence coefficients of pressure-induced shifts have been measured for N2-broadened transitions in the ν2 band of HCN. Line positions and intensities were also determined. A total of 34 laboratory absorption spectra, recorded at 0.002-0.005 cm−1 resolution with two different Fourier transform spectrometers, were used in the determination of the spectral line parameters. The total pressures of the HCN-N2 samples ranged from less than 1 torr up to nearly 1 atm, and temperatures were between 211 and 300 K. A multispectrum nonlinear least-squares fitting technique employing a modified Voigt line profile, including speed dependence and line mixing via the off-diagonal relaxation matrix formulation, was used in the analysis. Speed-dependence parameters were determined in the P and R branches of the ν2 band of H12C14N, and in the ν2 Q branches of H12C14N and H13C14N the off-diagonal relaxation matrix elements that characterize line mixing were included in the analysis to fit the data. Present results are compared with previous measurements reported in the literature. 相似文献
107.
Mössbauer measurements on octaethylhaemin have been made between 4.2 and 300 K, and (at the lower temperature) in applied magnetic fields of up to 50 kG. From a spin hamiltonian treatment the saturation value of the hyperfine field at the 57Fe nucleus is found to be 495 kG, and the splitting parameter for the ferric ion levels by the axial ligand field is D = 8.0 cm?1. The electric field gradient 1/2e2qQ = +0.93 mm s?1. 相似文献
108.
Perfluoro--propylbromine(V) tetrafluoride has been prepared by fluorination of perfluoro--propyl bromide at 0°C with elemental fluorine. It has been characterized by 19FNMR, mass spectroscopy and elemental analysis. 相似文献
109.
Passage of undiluted elemental fluorine gas through a radiofrequency discharge region is known to produce atomic fluorine. Reaction of atomic fluorine with bromobenzene vapor gave the corresponding bromofluorobenzene isomers and small amounts of fluorobenzene and difluorobenzene isomers. From the isomer distributions the substitution of the atomic fluorine in observed to be more selective than previously thought. 相似文献
110.
The cross sections and transverse spin asymmetries in the hard exclusive electroproduction of decuplet baryons are calculated in the large N(c) limit and found to be comparable to that of octet baryons. Large N(c) selection rules for the production amplitudes are derived, leading to new sensitive tests of the spin aspects of the QCD chiral dynamics both in the nonstrange and strange sectors. Importance of such studies for the reliable extraction of the pion form factor from pion electroproduction is explained. 相似文献