A numerical test of analytical methods for reduction of IR and MW spectra of NaCl chi1sigma+ to parameters of radial functions

Two methods for direct inversion of IR and MW spectra of diatomic molecules--a deformational self-consistent procedure (DS-cP) and a computer program RADIATOM based on hypervirial perturbation theory are tested numerically. The test calculations for NaCl chi1sigma+ confirm that the RADIATOM program does not produce sufficiently accurate radial parameters and energy term values for their export to other utilities employed in the spectral analysis of diatomic systems.     

High-Resolution Laser Spectroscopy of YbCl: The A(2)Pi-X(2)Sigma(+) Transition

The A(2)Pi-X(2)Sigma(+) transition of (174)Yb(35)Cl and (172)Yb(35)Cl 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 A(2)Pi state are A(e) = 1491.494(2) cm(-1) and R(e) = 2.4433(1) ?, and for the X(2)Sigma(+) state, R(e) = 2.4883(2) ? and gamma(e) = 4.59(2) x 10(-3) cm(-1). The interaction between the X(2)Sigma(+) and A(2)Pi states has been investigated and is shown to be the main contributor to the spin-rotation splitting in the ground state. Copyright 2000 Academic Press.     

Low defect-density polycrystalline silicon for high performance thin film transistors

Polysilicon films formed by the decomposition of silane in a LPCVD reactor at temperatures around 630°C have been used to make thin film transistors. It has been found that deposition of the polysilicon at lower pressures than previously results in improved performance and this is related to the crystallographic structure of the material. The structure of polysilicon deposited at pressures down to 2.5 mTorr has been investigated and the results presented.     

Urinary cotinine fluoroimmunoassay for smoking status screening adapted to an automated analyser.

A polarization fluoroimmunoassay for cotinine, a major metabolite of nicotine, has been adapted for fully automated screening of urine samples on the Abbott TDx analyser. The method has sensitivity and specificity suitable for the discrimination of active smokers from non-smokers (including passive smokers) by application of a cut-off at 0.5 mg l-1 of total urinary cotinine. Most active smokers' urine gave results over 1 mg l-1, whereas apparent levels in non-smokers were 0.08 mg l-1 or lower. A result for one sample can be obtained in about 5 min and a throughput of 80 samples h-1 can be maintained for large-scale screening applications.     

Rotational analysis of the A2Σ+ → X2Π system of OT. Merged molecular constants for OT A2Σ+, v ≤ 4 and X2Π, v ≤ 3

The A²Σ⁺ → X²Π band system of OT was observed for the first time. Fourteen bands with 0 ≤ v′ ≤ 4 and 0 ≤ v″ ≤ 3 were photographed at high resolution and rotationally assigned. Fitted values of 18 effective parameters of the model Hamiltonians used to describe individual vibrational levels of the two states are determined by least-squares from the data of each band. Multiple determinations of the parameters are merged to obtain single-valued estimates of the same parameters, as well as Dunham coefficients describing their vibrational dependence.     

Rotational analysis of the A2Πi → X2Πr band system of the sulfur monoxide cation,SO+

Six bands in the 0-v″ progression and three bands in the 1-v″ progression of the A²Π_i → X²Π_r visible system of SO⁺ have been recorded photoelectrically and rotationally assigned. Molecular constants for v′ = 0 and 1 in the A state and for v″ = 4–9 in the X state have been obtained using direct fitting and merging techniques.     

A probe of the relative rate of interconversion of carbonium ion conformers vs proton loss in 9-hydroxy-10-methyldecahydronaphthalenes

Deutero-alcohol (2b) was prepared and dehydrated with H₂SO₄Ac₂OHOAc to give a kinetic isotope effect demonstrating anion mobility within the intermediate carbocation-anion ion pair.