The Coriolis Interaction between the v2 = 1 and v3 = 2 States of Nitrosyl Bromide: Anomalous Quadrupole Patterns and Interstate Transitions in the Millimeter-Wave Spectrum.
The millimeter-wave rotational spectra of 79BrNO and 81BrNO in the v2 = 1 and v3 = 2 vibrational states have been reinvestigated. Measurements of the rotational spectrum in the region of maximum c-type Coriolis interaction between the two states allowed the previous analysis to be extended to account for some uncommon effects. For the most perturbed transitions the nuclear quadrupole hyperfine structure arises from coupling of not only the bromine nucleus, but also the nitrogen nucleus with the rotational angular momentum. These effects were satisfactorily fitted with a Hamiltonian describing Coriolis coupling in a molecule with two quadrupolar nuclei. The successful analysis of pure rotational transitions then allowed accurate prediction of rovibrational transitions, six of which were measured for 79BrNO and four for 81BrNO. Copyright 1998 Academic Press.
Hyperfine structure analysis of stibine in the ground and in the v4 = 1 states
Abstract The two isotopic forms of stibine, 121 SbH 3 and 123 SbH 3 , have been spectroscopically studied with high resolution. Pure quadrupole resonances both in the ground and in the v 4 = 1 states have been observed using the infrared-radiofrequency double resonance technique in a CO 2 laser cavity. Characteristic hyperfine patterns resulting from direct l -type doubling transitions in the v 4 = 1 state have been measured by microwave spectroscopy. The hyperfine pattern in the ground state is reproduced following the standard treatment. Strong vibration-rotation interactions between the v 2 = 1 and v 4 = 1 states affect the observed spectrum in the v 4 = 1 state. A refined treatment of the vibration-rotation interactions between the hyperfine levels in this state was necessary in order to adequately analyze the experimental data. Quadrupole interaction parameters for a degenerate state of a symmetric-top molecule have been determined for the first time.
Mechanical behaviour and durability of high volume fly ash cementitious composites
The purpose of this research is to separate different morphological particles of ASTM class F fly ash, and study their effect on mechanical behaviour and durability of high volume cementitious mixtures. In this research wet separation of raw fly ash is carried out, which resulted in three layers of different morphological particles. The first layer of particles float, comprise of about 1-5% of fly ash, is identified as cenospheres or hollow spheres. The second layer of particles is measured to be 55-60% of raw fly ash and consisting of porous spherical and rounded particles rich in Si and Al. The third layer particles is measured to be about 35-40% of raw fly ash. High volume fly ash cementitious composites containing second or third layer particles are tested under compression and bending, highlighting a higher strength and ductility in comparison to cementitious ones containing raw fly ash particles. KEYWORDS. Cementitious matrix; Raw fly ash; Second layer particles; Third layer particles.