High-resolution Fourier-transform IR spectroscopic determination of impurities in silicon tetrafluoride and silane prepared from it

The impurity compositions of silicon tetrafluoride and silane prepared from it have been determined by high-resolution Fourier-transform IR spectroscopy. In the spectra of SiF4 samples differing in purity, we have identified rovibrational bands arising from Si2F6O, SiF3OH, HF, SiF3H, SiF2H2, SiH3F, CH4, CO2, and CO impurities. Their detection limits lie in the range 9 x 10(-5) (CO2) to 3 x 10(-3) mol % (Si2F6O). In the spectra of SiH4 samples of different purity, we have detected CH4, CO2, SiF3H, SiF2H2, and SiF4 impurities. Their detection limits lie in the range 8 x 10(-5) (CO2) to 1 x 10(-3) mol % (SiF4)

IR CRYOSPECTROSCOPY OF LIQUEFIED HYDRIDES OF IVA-VIA GROUP ELEMENTS AND THEIR SOLUTIONS IN LIQUEFIED INERT GASES

Author Institution: Institute of Chemistry of High-Purity Substances, Russian Acad. Sci.; Institute of Chemistry of High-Purity Substances, St. Paterburg state UniversityThe IR absorption spectra of the $SiH_{4}$ and $GeH_{4}$ solutions in LKr at length of multi-pas cell 1.6 m were studied by the specially developed technique. The overtone and combined bands up to 3rd order inclusively were observed and have been studied for the first time. The spectra of the solutions of $PH_{3}$, $ASH_{3}$, and $H_{2}$Se In LKr were studied in the fundamental region. $NH_{3}$ and $H_{2}O$ do not dissolve in LKr due to a more pronounced self-association comparing with other hydrides. The temperature dependence of absorption spectra of the liquefied $NH_{3}$, $PH_{3}$, $ASH_{3}$, $H_{2}S$ and $H_{2}Se$ have been considered in detail in the fundamental, overtone, and combined frequency regions. The results obtained made it possible to specify or to find for the first time the spectral parameters of many week bands in the IR spectra of hydrides, as well as to satiate the energy of intermolecular H-bonding in the liquid $H_{2}$s, $H_{2}Se$, $NH_{3}$

Buffer-gas effect on the rotovibrational line intensity distribution: Analysis of possible mechanisms

Line intensities Am (|m| ≤ 4) of the HF fundamental band (T=293 K) are found to decrease linearly with the buffer-gas (Xe) density (DXe = 2.6-16 Amagat). The obtained slopes Δ1(m) of the Am(d)/ Am(0) vs. dXe plots are maximum at |m| =1 (Δ1(1) ≈ Δ1(-1) = 1.7(4) * 10-2Amagat-1) and rapidly drop with |m| . Many possible mechanisms are considered; the most effective one appears to be the HF-Xe bimer formation, with the equilibrium constant strongly depending on the rotational quantum number. The rigid-rotator approximation used gives the density derivatives considerably smaller than the measured ones. The disbalance may be lessened for vibrating rotators by allowance for the interband intensity transfer induced by the vibrational modulation of short-range forces