The Extraction of Vanadium from Titaniferous Iron Ores

TITANIFEROUS magnetites, often called titano-magnetites, occur in many parts of the world and they mostly contain a variable, but significant content of vanadium. In fact, most ilmenites also contain a small vanadium content

HIGH-RESOLUTION STIMULATED RAMAN SPECTROSCOPY OF THE ν1\nu_{1} BAND OF SiH4SiH_{4}

1. A Owyoung, C. W. Patterson, and R. S. McDowell, Chem. Phys. Lett. 59, 156 (1978). 2. R. S. McDowell, C. W. Patterson, and A. Owyoung, J. Chem. Phys., in press. 3. A. Cabana, D. L. Gray, A. G. Robiette, and G. Pierre, Mo1. Phys. 36, 1503 (1978)Author Institution:A Doppler-limited isotropic Raman spectrum of the symmetric stretching fundamental $(\nu_{1})$ of $^{28}SiH_{4}$ has been recorded using high-sensitivity “quasi-cw” inverse Raman spectroscopy. Unlike the corresponding fundamentals of $^{12}CH_{4}$ (1) and $^{13}CH_{4}$ (2), this band exhibits compact non-overlapping J manifolds that extend over about $5 cm^{-1}$. Since $\nu_{1}$ and the infrared-active stretch $\nu_{3}$ reported by Cabana et al. (3) and the Raman frequencies of $\nu_{1}$ Q (0) through Q(14). The results confirm the infrared analysis (3), in which several perturbation-allowed $\nu_{1}$ transitions were identified in absorption, but the molecular constants are much better determined by the inclusion of the Raman data. Significant intensity perturbations occur at higher J due to a break down of the selection rule $\Delta=0$ (N is the index distinguishing between levels of the same J and rovibrational symmetry), and have been quantitatively accounted for

The two-dimensional anharmonic oscillator I: vibration-rotation constants of fulminic acid, HCNO

The lowest-wavenumber vibration of HCNO and DCNO, ν5, is known to involve a largeamplitude low-frequency anharmonic bending of the CH bond against the CNO frame. In this paper the anomalous vibrational dependence of the observed rotational constants B(v5, l5), and of the observed l-doubling interactions, is interpreted according to a simple effective vibration-rotation Hamiltonian in which the appropriate vibrational operators are averaged in an anharmonic potential surface over the normal coordinates (Q5x, Q5y). All of the data on both isotopes are interpreted according to a single potential surface having a minimum energy at a slightly bent configuration of the HCN angle ( 170°) with a maximum at the linear configuration about 2 cm−1 higher. The other coefficients in the Hamiltonian are also interpreted in terms of the structure and the harmonic and anharmonic force fields; the substitution structure at the “hypothetical linear configuration” determined in this way gives a CH bond length of 1.060 Å, in contrast to the value 1.027 Å determined from the ground-state rotational constants. We also discuss the difficulties in rationalizing our effective Hamiltonian in terms of more fundamental theory, as well as the success and limitations of its use in practice

LOCAL MODE BEHAVIOR IN THE STRETCHING OVERTONES OF GERMANE

Author Institution: Department of Chemistry, University of Reading Whiteknights, Reading; Molecular Spectroscopy Division, National Bureau of Standards; Department of Chemistry, Concordia UniversityThe Ge-H stretching overtone band near $4155 cm^{-1}$ has been recorded with Doppler-limited resolution, for both natural $GeH_{4}$ and enriched $^{74}GeH_{4}$, using a difference-frequency spectrometer. The structure has been analyzed in terms of a closely-coupled $A_{1} + F_{2}$ pair of bands for each isotopic species. The vibrational modes are best described not as $2\nu_{1}, \nu_{1} +\nu_{3}$ or $2\nu_{3}$ levels but rather as a (2000) local mode cluster. The rotational coupling between the $A_{1}$ and $F_{2}$ substates leads to a complex spectrum, which has been successfully modeled and fitted to around $J=10$ to 12. Over 1650 assignments for the five isotopic species have been fitted with a standard deviation of around $3^{*}10^{-4} cm^{-1}$

The two-dimensional anharmonic oscillator II: the microwave spectrum of silyl isocyanate, SiH3NCO

The J + 1 ← J transitions (J = 2, 3, 4, 5, and 6) in the microwave spectrum of SiH3NCO have been assigned for the vibrational ground state and for the vibrational states v10 = 1, 2, and 3. The results for v10 = 0 confirm earlier work. The vibration-rotation constants show a remarkable variation with v10 and l10. To a large extent the anomalous behavior of these constants has been explained in terms of a strongly anharmonic potential function for the ν10 vibrational mode

ANALYSIS OF THE v3v_{3} AND v1v_{1} INFRA-RED BANDS OF GeH4GeH_{4}

Author Institution:The high-resolution infra-red spectrum of $GeH_{4}$ in the region 2020 to $2200 cm^{-1}$ has been analysed. Most of the observed lines have been assigned to transitions of the $v_{3}$ and $v_{1}$ bands of the five naturally-occuring isotopic species. The spectrum has been fitted by diagonalizing the $v_{3} = 1$ and $v_{1} = 1$ hamiltonians coupled by the dominant vibration-rotation interaction term. For each isotopic species, about one hundred transitions have been fitted with an overall standard deviation of $0.006 cm^{-1}$, using only ten adjustable parameters. The five sets of parameters obtained are consistent with the expected isotope effects