Experimental retrieval of target structure information from laser-induced rescattered photoelectron momentum distributions

We have measured two-dimensional photoelectron momentum spectra of Ne, Ar, and Xe generated by 800-nm, 100-fs laser pulses and succeeded in identifying the spectral ridge region (back-rescattered ridges) which marks the location of the returning electrons that have been backscattered at their maximum kinetic energies. We demonstrate that the structural information, in particular the differential elastic scattering cross sections of the target ion by free electrons, can be accurately extracted from the intensity distributions of photoelectrons on the ridges, thus effecting a first step toward laser-induced self-imaging of the target, with unprecedented spatial and temporal resolutions.     

Internal inelastic scattering satellite probed by molecular-frame photoelectron angular distributions from CO2

The molecular-frame photoelectron angular distribution (MFPAD) of the satellite accompanying the C 1s photoline of the CO2 molecule has been measured at the C 1s(2sigmag)-->4sigmau* shape resonance, using electron-ion multicoincidence momentum spectroscopy. The observed MFPAD indicates that the conjugate satellite is excited by internal inelastic scattering. In this scenario, a photoelectron is ejected from the C 1s(2sigmag) orbital along the molecular axis and collides with an O lone-pair electron in the highest occupied molecular orbital 1pig. Then one of the colliding electrons is trapped to the lowest unoccupied molecular orbital 2piu*, while the other is emitted as a satellite photoelectron of sigmag symmetry, losing the information of the original photoelectron emission direction and parity.     

New nonlinear-laser effects in YbVO4 crystal: Sesqui-octave stokes and anti-Stokes comb generation and the cascaded self-frequency “tripling” of χ(3)-Stokes components under a one-micron picosecond pumping

We report the experimental investigations of nonlinear-laser effects in vanadate YbVO₄ under a onemicron picosecond Nd³⁺:Y₃Al₅O₁₂ laser pumping. In this tetragonal host-crystal for Ln³⁺ lasants, for the first time, we excited more than one-and-a-half octave (≈11661 cm^?1) Raman-induced Stokes and anti-Stokes generation combs and observed a multistep cascaded parametric χ⁽³⁾ lasing in the deep-blue spectral region. All generation lines were identified and attributed to the SRS-promoting vibration mode of the crystal (ω_SRS ≈ 897 cm^?1). We classified the ytterbium vanadate as a promising material for Raman frequency converters, wideband χ⁽³⁾-nonlinear comb generators, and as a gain medium for solid-state lasers.     

Photoresponsive inorganic polymers obtained by metal alkoxides

The polymerization of metal alkoxides was carried out in organic solvents and light responsive polymers were obtained. As starting materials for polymerization, Ti(OBu)₄, Zr(OBu)₄, Nb(OEt)₅, and Ta(OEt)₅ were used. The polymerization yield roughly corresponds to the formation of TiO₂, ZrO₂, NbO₂(OEt), and TaO₂(OEt), respectively. The polymers obtained are paramagnetic and all give similar (dark) ESR spectra. When illuminated by visible light, a new ESR absorption is detected in the vicinity of g = 2.00, or 330–340 mT (for 9.450 GHz) region. The formation and decay rates of this ESR absorption was measured. The decay rate constants obtained from the formation curves were larger than those obtained from the decay curves, indicating relatively short lived species are formed during light illumination. The polymers thus prepared have photocatalytic activity and can photolyze 1 : 1 methanol/water system with visible light. Other possible uses of these polymers as paramagnetic or photochromic materials are discussed.     

Electrical and thermal properties of intercalation compound FexTiS2

Intercalation phenomena of guest Fe atoms into van der Waals gaps of the host 1T - TiS₂ layered crystal have been studied by transport measurements. These experimental results, together with other data, are indicative of the presence of spin-up and spin-down bands produced by the host-guest interactions and understood in terms of an itinerant band picture, in agreement with recent band calculations.     

Sharpness and amplitude envelopes of broadband noise

This paper discusses how amplitude envelope shapes, sound-pressure level, and duration of broadband noise affect sharpness and brightness. In the first experiment, sharpness, brightness, and similarity were judged for paired stimuli by 13 subjects. The stimuli consisted of broadband noise with different types of amplitude envelopes, sound-pressure levels, and duration. Experimental results were analyzed with a multidimensional scaling technique. In addition, the second experiment measuring the point of subjective equality (PSE) of sharpness was carried out for four subjects. The results of these two experiments showed large individual differences in sharpness judgment, difficulty in brightness judgment for the stimuli used in the experiments, and influence of the amplitude envelope shapes on sharpness. The individual differences observed in sharpness judgment were explained by the differences between weights given to two psychological dimensions: loudness and subjective duration. This study forms a basis for understanding sharpness of nonsteady sounds.     

Infrared laser stark spectroscopy of ammonia

Refined values for molecular constants of¹⁴NH₃ and less precise values for those of¹⁵NH₃ and¹⁴NH₂D were obtained with laser Stark spectroscopy. Paper was prepared for presentation at FICOLS