Lowest Overtone and Combination Levels of DCCI: The Fermi Resonance v3 = 1/v5 = 2.
The infrared spectrum of deuterated monoiodoacetylene DCCI in the region of 220-550 cm-1 has been studied at a resolution of 0.0020 cm-1. The hot bands nu3 <-- nu15 and 2nu0,25 <-- nu15 have been analyzed by considering especially the Fermi resonance v3 = 1/v5 = 2. In the next layer of the hot bands (nu3 + nu5)1 <-- nu3, (nu3 + nu5)1 <-- 2nu0,25 and 3nu1,35 <-- 2nu25 the same Fermi resonance appears between v3 = v5 = 1 and v5 = 3. In addition, various l resonances at the overtone levels have been considered. As a result, the vibrational and rotational constants for the level systems v3 = 1/v5 = 2 and v3 = v5 = 1/v5 = 3 together with the resonance parameters have been obtained. Copyright 1999 Academic Press.
Vibration-Rotation Interactions in Bending and CBr Stretching Fundamental Band Systems ν3, ν4, and ν5 of Monobromoacetylene
Abstract High-resolution vibration-rotation spectra of a sample of natural monobromoacetylene (HCCBr) have been recorded with the Bruker IFS 120 Fourier spectrometer in the region of the bending and CBr stretching fundamentals. Altogether 23 bands belonging to HCC79Br and 23 bands belonging to HCC81Br isotopic species have been analyzed rotationally, yielding accurate vibrational term values and rotational constants. Coriolis-, rotational l-, and Fermi-resonance interactions have been observed and analyzed in some of the bands.
Experimental energy barriers to anions transporting through nanofiltration membranes.
Environmentally relevant contaminants fluoride, chloride, nitrate, and nitrite face Arrhenius energy barriers during transport through nanofiltration (NF) membranes. The energy barriers were quantified using crossflow filtration experiments and were in the range of 7-17 kcal·mol(-1), according to ion type and membrane type (Filmtec NF90 and NF270). Fluoride faced a comparatively high energy barrier for both membranes. This can be explained by the strong hydration energy of fluoride rather than other ion properties such as bare ion radius, fully hydrated radius, Stokes radius, diffusion coefficient, or ion charge. The energy barrier for fluoride decreased with pressure, indicating an impact of directional force on energy barriers. The influence of temperature-induced pore radius variability and viscosity on energy barriers was considered. The novel link between energy barriers and ion properties emphasizes the importance of ion hydration and/or partial dehydration mechanisms in determining transport in NF.