When energized sufficiently either vibrationally or electronically, ROH (where R is methyl or ethyl) can dissociate to form H atoms and RO radicals. We have determined the translational energy release (〈ETr 〉=0.82Eavl ) and angular distribution (β=−0.60±0.03) from the laser induced fluorescence spectra of H atoms produced in the 193 nm photodissociation of CD3OH. We have also determined that the quantum yield for producing H from CD3OH is 0.86±0.10. In contrast, the reaction of O(1D)+CH4 which produces vibrationally excited CH3OH, has a quantum yield for producing H atoms of roughly 0.25 with only 22% of the available energy released as translation. We conclude that although the total available energy is the same in both cases, the dissociation of photoexcited methanol is prompt whereas the dissociation of chemically activated methanol shows some degree of internal vibrational equilibration.

We examined spindle elongation in anaphase in Saccharomyces cerevisiae cells mutated for the kinesin-5 motor proteins Cin8 and Kip1. Cells were deleted for KIP1 and/or expressed one of two motor-domain Cin8 mutants (Cin8-F467A or Cin8-R196K, which differ in their ability to bind microtubules in vitro, with Cin8-F467A having the weakest ability). We found that, in kinesin-5-mutated cells, predominantly in kip1Δ cin8-F467A cells, anaphase spindle elongation was frequently interrupted after the fast phase, resulting in a mid-anaphase pause. Expression of kinesin-5 mutants also caused an asymmetric midzone location and enlarged midzone size, suggesting that proper organization of the midzone is required for continuous spindle elongation. We also examined the effects of components of the FEAR pathway, which is involved in the early-anaphase activation of Cdc14 regulatory phosphatase, on anaphase spindle elongation in kip1Δ cin8-F467A cells. Deletion of SLK19, but not SPO12, eliminated the mid-anaphase pause, caused premature anaphase onset and defects in DNA division during anaphase, and reduced viability in these cells. Finally, overriding of the pre-anaphase checkpoint by overexpression of Cdc20 also eliminated the mid-anaphase pause and caused DNA deformation during anaphase in kip1Δ cin8-F467A cells. We propose that transient activation of the pre-anaphase checkpoint in kinesin-5-mutated cells induces a Slk19-dependent mid-anaphase pause, which might be important for proper DNA segregation.

Branching ratio in the HD+OH reaction: A full-dimensional quantum dynamics study on a new ab initio potential energy surface Quasiclassical trajectory studies of the chlorine-hydrogen system. III. Branching ratio, energy partitioning, and angular distribution in the reaction of Cl atoms with HDThe dynamical stereochemistry of the reaction of hot F atoms with HD is discussed with reference to the measured branching ratio using both exact and model classical trajectory computations. It is argued that the dominant effects are due to the shift of the center of mass from the center of charge. In particular this leads to enhanced reactivity of the D end of the molecule due both to reorientation of the molecule and to the recrossing of the barrier. The observed preference for reaction at the H end is attributed to HD rotational excitation reflecting however the shape of the potential energy surface and not the longer arm of the H atom about the center of mass. Measuring the reaction cross sections for rotationally cold HD will provide a critical test of our understanding of the dynamics.

Chemically stable quantum-confined 2D metals are of interest in next-generation nanoscale quantum devices. Bottom-up design and synthesis of such metals could enable the creation of materials with tailored, on-demand, electronic and optical properties for applications that utilize tunable plasmonic coupling, optical non-linearity, epsilon-near-zero behavior, or wavelengthspecific light trapping. In this work, we demonstrate that the electronic, superconducting and optical properties of air-stable two-dimensional metals can be controllably tuned by the formation of alloys. Environmentally robust large-area two-dimensional InxGa1-x alloys are synthesized by Confinement Heteroepitaxy (CHet). Near-complete solid solubility is achieved with no evidence of phase segregation, and the composition is tunable over the full range of x by changing the relative elemental composition of the precursor. The optical and electronic properties directly correlate with alloy composition, wherein the dielectric function, band structure, superconductivity, and charge transfer from the metal to graphene are all controlled by the indium/gallium ratio in the 2D metal layer.

The phase control of molecular absorption, first proposed by Shapiro, Hepburn, and Brumer was accomplished with CH 3 I using the technique of Chen, Yin, and Elliott. Red light ͑ near 603 nm͒ was focused in a cell containing CH 3 I gas at a pressure around 1 Torr. The emerging light, a coherent mixture of the fundamental and the third harmonic ͑ near 201 nm͒, was refocused on a molecular beam of CH 3 I and multiphoton ionization was detected. Ionization was by two simultaneous processes: a uv photon absorption followed by the absorption of two red photons ͑1ϩ2 process͒ and an absorption of three red photons followed by the absorption of two more ͑3ϩ2 process͒. Because of the sharp resonant Rydberg transition at 201 nm, the one and three photon matrix elements dominate the transition. Interference between the amplitudes of these two paths was demonstrated by varying the pressure and, hence, the index of refraction of the Ar gas in a tuning cell where the two light beams were refocused by two spherical mirrors. The modulation depth varied with wavelength but had a maximum of 75%, the largest modulation so far observed in this kind of experiment.