The photodissociation of dimethyl sulfide (CH
3SCH
3) at 229
nm has been studied employing a combination of velocity map imaging and time-of-flight resonance-enhanced multiphoton ionization ...techniques to detect the CH
3 products. Translational energy and recoil angle distributions as well as rotational state populations have been determined for the CH
3 photofragments formed in the ground vibrational state. The electronic excitation of CH
3SCH
3 to the first absorption band is found to produce fast CH
3S+CH
3 (
v=0) recoiling products with a negative spatial anisotropy parameter of
β=−0.85±0.05. The CH
3 (
v=0) products are rotationally cold, the rotational distribution peaking at
N′′=3–4.
One of the most remarkable properties of the nitrogen-vacancy (NV) center in diamond is that optical illumination initializes its electronic spin almost completely, a feature that can be exploited to ...polarize other spin species in their proximity. Here we use field-cycled nuclear magnetic resonance (NMR) to investigate the mechanisms of spin polarization transfer from NVs to 13C spins in diamond at room temperature. We focus on the dynamics near 51 mT, where a fortuitous combination of energy matching conditions between electron and nuclear spin levels gives rise to alternative polarization transfer channels. By monitoring the 13C spin polarization as a function of the applied magnetic field, we show 13C spin pumping takes place via a multi-spin cross relaxation process involving the NV- spin and the electronic and nuclear spins of neighboring P1 centers. Further, we find that this mechanism is insensitive to the crystal orientation relative to the magnetic field, although the absolute level of 13C polarization - reaching up to ~3% under optimal conditions - can vary substantially depending on the interplay between optical pumping efficiency, photo-generated carriers, and laser-induced heating.
CARICOMP is a regional scientific program to study land-sea interaction processes in the Caribbean coastal zone. It has been collecting data since 1992, when a Data Management Centre was established ...at the University of the West Indies in Jamaica. Initially it focuses on documenting
the structure and productivity of major coastal communities (mangrove forests, seagrass meadows and coral reefs) at relatively undisturbed sites in diverse physical settings. Second, by regular recording of physical and biological parameters, it monitors for change, seeking to distinguish
natural from anthropogenic disturbance. Third, it constitutes a regional network of observers, able to collaborate on studies of region-wide events. Examples are presented of the diverse data sets collected by the Program.
Studies of the physical properties of Trans-Neptunian Objects (TNOs) are a powerful probe into the processes of planetesimal formation and solar system evolution. JWST will provide unique new ...capabilities for such studies. Here we outline where the capabilities of JWST open new avenues of investigation, potential valuable observations and surveys, and conclude with a discussion of community actions that may serve to enhance the eventual science return of JWSTs TNO observations.
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