103 research outputs found
Collisional depolarization of state selected (J,M J ) BaO A 1Σ+ measured by optical–optical double resonance
No full textThe optical–optical double resonance (OODR) technique is used to investigate the change in magnetic quantum number (M) a state selected molecule undergoes on collision with other molecules. A first linearly polarized dye laser prepares A 1Σ+BaO(v = 1) in the J = 1, M = 0 sublevel. The extent of collisional transfer to other M sublevels of both J = 1 and J = 2 is then probed by a second polarized dye laser which induces fluorescence from the C 1Σ+ state. Elastic collisions (ΔJ = 0) between BaO (A 1Σ+) and CO2 are observed to change M from 0 to ±1 leaving J unchanged. The total elasticM‐changing cross section is σΔM CO2 = 8.4±2.4 Å2. Inelastic collisions (ΔJ = +1’ which transfer molecules to j = 2 also cause M changes. with both Ar and CO2 as collision partners. M, the s p a c e‐f i x e d projection of J, is found to be neither conserved nor randomized. Quantum atom–diatom collision models with quantization axis along the relative velocity vector are considered. Transition amplitudes in this system are evaluated using the l‐dominant and CS approximations
LIFETIMES, MAGNETIC MOMENTS AND SPIN SPLITTINGS OF HIGH ROVIBRATIONAL LEVELS OF R STATE
No full text. A. J. Merer, S. A. Morris, and Ch. Jungen, J. Mol. Spectrosc. 127, 425 (1988).Author Institution: Department of Chemistry, Virginia Commonwealth UniversityPrevisouly unassigned bands in the 3300 to 3450 A region of the absorption spectrum have recently been shown to be part of the R system whose upper state is the spin component of a state. This work systematically investigates lifetimes and magnetic moments of the high lying R state rovibrational levels excited by radiation in this region. These levels become progressively more perturbed as the and other background states are approached. From g values, which range from 0.009 to 0.037, zero-field spin splittings been R state spin components can be estimated at 24 to . It is surprising that R state lifetimes less than are observed since V state levels, from which R borrows oscillator strength, have lifetimes in the range
FLUORESCENCE SPECTRA OF PN AND BF
No full textAuthor Institution: Department of Chemistry, University of PennsylvaniaResonance fluorescence has been observed from the states of PN and BF. The species are produced in a microwave discharge and flowed into a fluorescence cell where they are optically excited by both molecular and atomic lamps. Vibronic transition probabilities for the PN system are obtained from observed band intensities and are compared with calculated Franck-Condon factors
THE OBSERVATION OF CONTINUUM-LIKE EMISSION IN A SUPERSONIC JET
No full text J. L. Hardwick, J. Mol. Spectrosc. 109, 85 (1985).Author Institution: Department of Chemistry, Virginia Commonwealth UniversityWhen is excited in the 280 - 340 nm region, its dispersed fluorescence displays both discrete and continuum-like components. Our bulb studies have shown that the continuum is enhanced by collisions, but persists in the low pressure limit where collisions during the excited state lifetime are unlikely. This work in a supersonic jet confirms that continuum emission persists under essentially collision-free conditions. The continuum emission is identified both by dispersing the fluorescence and by observing its long (relative to the discrete emission) lifetime. The amount of continuum compared to discrete emission is monitored as the excitation wavelength is scanned through the region of the T and V systems bands. Continuum emission is excited almost everywhere; an apparent continuum in excitation corresponds to the one seen in emission. In the region of excitation bands the discrete and continuum emissions do not track each other; the continuum/discrete ratio varies with J. The origin of continuum-like emission is discussed using a model proposed by to explain similar emission for
Zeeman quantum beat spectroscopy of higher rovibrational levels of the V 1B2 state of carbon disulfide
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