Two-photon photoemission is a promising new technique that has been developed for the study of electron dynamics at interfaces. A femtosecond laser is used to both create an excited electronic distribution at the surface and eject the distribution for subsequent energy analysis. Time- and momentum-resolved two-photon photoemission spectra as a function of layer thickness fully determine the con...

introduction: the present study evaluated the element distribution in completely set calcium-enriched mixture (cem) cement after application of 35% carbamide peroxide, 40% hydrogen peroxide and sodium perborate as commercial bleaching agents using an energy-dispersive x-ray microanalysis (edx) system. the surface structure was also observed using the scanning electron microscope (sem). methods ...

The 364 nm photoelectron spectra of the dehydrobenzoquinone (1•-) and benzoquinonide (2-) anions are reported. For 1•-, the unambiguous assignment of the origin peak yields an electron affinity (EA) of 1.859 ( 0.005 eV. Several vibrational modes of 1 are also reported. Another minor feature at higher electron binding energy is also observed in the spectrum of 1•-. This band does not contain any...

The theoretical treatment of cycle-effects on total pi-electron energy, mainly elaborated by Nenad Trinajstic and his research group, is re-stated in a general and more formal manner. It enables to envisage several other possible ways of measuring the cycle-effects and points at further directions of research.

Clusters of transition metals, W, Re, and Os, upon encapsulation within a single-walled carbon nanotube (SWNT) exhibit marked differences in their affinity and reactivity with the SWNT, as revealed by low-voltage aberration-corrected high-resolution transmission electron microscopy (AC-HRTEM). Activated by an 80 keV electron beam, W reacts only weakly with the SWNT, Re creates localized defects...

A gaseous nanocalorimetry approach is used to investigate effects of hydration and ion identity on the energy resulting from ion-electron recombination. Capture of a thermally generated electron by a hydrated multivalent ion results in either loss of a H atom accompanied by water loss or exclusively loss of water. The energy resulting from electron capture by the precursor is obtained from the ...

Uranium chlorides are important in actinide chemistry and nuclear industries, but their chemical bonding and many physical and chemical properties are not well understood yet. Here, we report the first experimental observation of two gaseous uranium hexachloride anions, UCl6 (-) and UCl6 (2-), which are probed by photoelectron spectroscopy in conjunction with quantum chemistry calculations. The...

Protein components of the U6 snRNP (Prp24p and LSm2-8) are thought to act cooperatively in facilitating the annealing of U6 and U4 snRNAs during U4/U6 di-snRNP formation. To learn more about the spatial arrangement of these proteins in S. cerevisiae U6 snRNPs, we investigated the structure of this particle by electron microscopy. U6 snRNPs, purified by affinity chromatography and gradient centr...