Showing papers on "Full width at half maximum published in 1980"
TL;DR: In this paper, the inelastic scattering of low-energy (20 meV), monoenergetic He nozzle beams from a LiF(001) surface along the $〈100〉$ direction was investigated.
Abstract: Preliminary results are reported on the inelastic scattering of low-energy (20 meV), monoenergetic ($\frac{\ensuremath{\Delta}v}{v}=0.8%$ full width at half maximum) He nozzle beams from a LiF(001) surface along the $〈100〉$ direction. The time-of-flight spectra reveal both broad and extremely sharp maxima. The broad maxima are attributed to a distribution of phonons of bulklike character with small momenta, while the sharp maxima indicate excitation of single discrete surface modes.
101 citations
TL;DR: In this article, total energy distribution (TED) curves of ions emitted from a gallium liquid metal ion source exhibit full width at half maximum (FWHM) value that increases from 5 to 30 eV with an increasing total current of 1-30 μA.
Abstract: Total energy distribution (TED) curves of ions emitted from a gallium liquid metal ion source exhibit full width at half maximum (FWHM) value that increases from 5 to 30 eV with an increasing total current of 1–30 μA An energy deficit of 4 eV at threshold supports a field evaporation mechanism of ion formation The lowest TED FWHM value of 5 eV corresponds to a source angular brightness of 20 μA/sr
98 citations
TL;DR: A one-beam prototype of a large twenty-four-beam phosphate-glass laser system has been built and tested and has demonstrated focusable power in excess of 750 GW/beam at 50-psec full width at half-maximum (FWHM) pulse duration and has delivered 165 J of focusable energy in a 500-p sec pulse duration.
Abstract: A one-beam prototype of a large twenty-four-beam phosphate-glass laser system has been built and tested. Basic design characteristics include Nd-doped phosphate glass, rod amplifiers up to 90-mm diam, the propagation of a circularly polarized beam, extensive spatial filtering and imaging, and the use of large-aperture Pockels cells. The prototype system has demonstrated focusable power in excess of 750 GW/beam at 50-psec full width at half-maximum (FWHM) pulse duration and has delivered 165 J of focusable energy in a 500-psec (FWHM) pulse. Maximum beam brightness has been measured to be 4 × 1019 W/cm2 · sr at a firing rate of 2 shots/hr. Peak-to-background energy contrast of 108 has been achieved with this system. A detailed description of the system design and performance is presented.
61 citations
TL;DR: In this paper, electron and ion energy spectra and electron pitch angle distributions for two sounding rocket flights in the dayside auroral zone are presented for two different sounding rocket missions.
Abstract: Electron and ion energy spectra and electron pitch angle distributions are presented for two sounding rocket flights in the dayside auroral zone. At times, effects of dc electric fields parallel to the magnetic field are evident in that: (1) within precipitation features, protons are decelerated by an amount of energy consistent with that which electrons gain and (2) electrons are sometimes aligned to within 3 deg (full width at half maximum) of the magnetic field. A maximum altitude for the accelerating region of several thousand kilometers is deduced from the narrow width of the pitch angle distribution and also from time-of-flight delays between the observation of accelerated electrons and decelerated protons.
46 citations
TL;DR: In this article, the linewidth of a single longitudinal mode AlGaAs/GaAs double heterostructure laser was measured using a Fabry-Perot interferometer with spacers of 30 cm, 3.2 m, and 10 m. The full width at half maximum was estimated to be less than 1 MHz when the current level exceeds 1.15 times the threshold.
Abstract: Interferometric measurement of the linewidth has been carried out on a single longitudinal mode AlGaAs/GaAs double heterostructure laser by using a Fabry-Perot interferometer with spacers of 30 cm, 3.2 m, and 10 m. The full width at half maximum was estimated to be less than 1 MHz when the current level exceeds 1.15 times the threshold, which was near the estimated theoretical limit.
37 citations
TL;DR: In this paper, the authors have reanalyzed previous data on the quasifree scattering at 590 MeV incident energy, from which they deduce a momentum distribution of the clusters in /sup 6/Li with a full width at half maximum around 120 MeV/c.
Abstract: We have reanalyzed previous data on the /sup 6/Li( p,pd) quasifree scattering at 590 MeV incident energy, from which the authors deduce a momentum distribution of the clusters ..cap alpha.. and d in /sup 6/Li with a full width at half maximum around 120 MeV/c. We find instead that the experimental results are compatible with a momentum distribution whose full width at half maximum is about 70 MeV/c, which is in agreement with other experimental findings and with the prediction of the cluster model.
27 citations
TL;DR: In this article, the Friedel-Anderson virtual bound state model for noble metal transition metal alloys was shown to be consistent with the photoelectron spectra of V, Cr, Mn, Fe, Co and Ni.
Abstract: The photoelectron spectra of V, Cr, Mn, Fe, Co and Ni dissolved in Au and of Mn dissolved in Ag have been measured using photon energies of 21.22 eV and 40.81 eV. The results appear to be consistent with the Friedel-Anderson virtual bound state model for noble metal-transition metal alloys, with clear evidence for the existence of localised states being seen in the spectra of AgMn, AuFe, AuNi and particularly AuCr. In AuCr the filled part of the spin-split Cr 3 d virtual bound state is found to be centred around 0.91+or-0.05 eV below the Fermi level with a full width at half maximum of about 0.70+or-0.10 eV. The localised states observed in AgMn and AuNi spectra lie approximately 2.84+or-0.05 eV and 0.40+or-0.05 eV below the Fermi level and have approximate widths of 0.78+or-0.10 and 0.59+or-0.10 eV, respectively.
24 citations
TL;DR: In this article, a planar photodiode with low dark current and high speed response was fabricated from low carrier density In 0.53 Ga 0.47 As grown by vapor-phase epitaxy.
Abstract: A punch-through type planar photodiode with low dark current and high speed response was fabricated from low carrier density In 0.53 Ga 0.47 As grown by vapor-phase epitaxy. Dark current density was 3.1 × 10-5A/cm2at 10 V bias. Rise time and full width at half maximum were 82 and 126 psec, respectively, at a bias above 4 V.
24 citations
TL;DR: In this paper, the azimuthal anisotropies in deep core level X-ray photoemission from atoms adsorbed on single-crystal surfaces have been observed and were found to be well described by a single-scattering model, thereby providing a new method for determining surface atomic geometries.
20 citations
TL;DR: Punchthroughact-Punch-throught ype InGaAs/InPp hotodiodes were made from high purity layers grown on (100) InP substrates by vapor phase epitaxy as discussed by the authors.
Abstract: Punch-throughact-Punch-throught ype InGaAs/InPp hotodiodes were made from high purity layers grown on (100) InP substrates by vapor-phase epitaxy. High-speed photoresponse to a mode-locked Nd:YAG laser was observed owing to as low carrier concentration as 1 X 10 15 cm -3 Full width at half maximum and rise time of the pulse response were 126 and 82 ps, respectively, at above 4 V. Dark current was affected by substrate etch pit densities and was 4.1 X 10 -4 A/cm 2 at 0.5 V B for a diode made from the layer on dislocation free substrate. A uniform photocurrent multiplication factor of 5 was obtained.
18 citations
TL;DR: In this paper, polymer-coated glass microspheres filled with DT fuel and argon seed gas were irradiated on the SHIVA 1.06-..mu..m laser using 4kJ 200 ps (full width at half maximum), Gaussian pulses.
Abstract: Polymer-coated glass microspheres filled with DT fuel and argon seed gas were irradiated on the SHIVA 1.06-..mu..m laser using 4-kJ 200 ps (full width at half maximum), Gaussian pulses. Measured light absorption, x-ray spectrum, neutron yields, and x-ray continuum images compare favorably with detailed computer simulations. Pusher neutron activation and argon line imaging diagnostics were utilized to measure fuel density. Fuel densities of 1-3 g/cm/sup 3/ or 5-15 times liquid DT density were inferred.
TL;DR: In this article, the 3p-to-1s X-ray emission of liquid silicon has been studied and the shape of the K beta emission band in the liquid closely resembles that expected of a simple metal, confirming the presence of four conduction electrons.
Abstract: The K beta (3p to 1s) X-ray emission band has been recorded for liquid silicon. It provides a determination of the 3p partial density of states in the valence band. Comparisons are made with equivalent emissions from the crystalline and amorphous solid phases. It is found that the 3p distribution broadens by 1.7 eV in the liquid (full width at half maximum amplitude) compared to crystalline Si. Practically no evidence remains of the sp mixing observed in the bottom of the valence band of the crystalline and amorphous phases. The shape of the K beta emission band in the liquid closely resembles that expected of a simple metal, confirming the presence of four conduction electrons.
TL;DR: In this paper, the absorption spectrum of ferric iron solutions of varying iron concentrations maintained at a constant pH of 1.0 and a constant ionic strength of 0.1 were studied.
Abstract: Ultraviolet absorbance spectra of ferric iron solutions of varying iron concentrations maintained at a constant pH of 1.0 and a constant ionic strength of 0.1 were studied. The experimental conditions of low pH minimized the formation of the hydrolytic FeOH2+ and Fe(OH)2+ species; thus, the spectra of iron solutions containing principally the Fe3+ species were recorded. The digitized spectral data were used to establish a model for the Fe3+ absorption spectrum that involves a Gaussian function with three parameters for each of the two absorption bands. These parameters were the wavenumber of the band maximum, ν‾max, the full width at half maximum intensity, Δν‾1/2, and the absorptivity of the band maximum, ɛmax. This study provided estimates for these parameters at 25°C for 0.1 ionic strength media.
TL;DR: In this article, the full width at half maximum (FWHM) resolution of the 1.17 MeV 60Co photopeak has been carried out as a function of neutron flux, electric field, time after application of bias and detector thickness.
Abstract: High-purity germanium detectors containing differing concentrations of [H2], [Si] and [O2] have been irradiated with fast neutrons from a 238Pu 9Be source (average energy 4.2 MeV). Measurements of the full width at half maximum (FWHM) resolution of the 1.17 MeV 60Co photopeak have been carried out as a function of neutron flux, electric field, time after application of bias and detector thickness.
TL;DR: In this paper, the authors investigated the broadening of bound exciton (BE) spectral lines at high impurity concentration for shallow acceptors in Si and found that broadening is mainly due to the effect of overlapping of wave functions and is calculated by taking account of the dominant binary interaction.
Abstract: We report on an investigation of the broadening of bound exciton (BE) spectral lines at high impurity concentration for shallow acceptors in Si. The broadening is mainly due to the effect of overlapping of wave functions and is calculated by taking account of the dominant binary interaction. The calculated spectral shape for a nondegenerate component in the BE spectra is found to be asymmetric. We find the broadening is strongly dependent on the impurity concentration. The calculated full width at half maximum is about 1 meV for a concentration of 5 \ifmmode\times\else\texttimes\fi{} ${10}^{17}$ ${\mathrm{cm}}^{\ensuremath{-}3}$ and is less than 0.01 meV for concentrations below 5 \ifmmode\times\else\texttimes\fi{} ${10}^{16}$ ${\mathrm{cm}}^{\ensuremath{-}3}$.
TL;DR: In this paper, the effect of the amplitude of the current modulation on experimental second derivative spectra measured using a tunable diode laser spectrometer is discussed, and two parameters, the distance between the zero crossings and the ratio of the minimal and maximal excursions, may be fit to an empirical hypersurface to obtain values for the peak absorbance, the actual half width and the collision-broadened half width.
Abstract: The effect of the amplitude of the current modulation on experimental second derivative spectra measured using a tunable diode laser spectrometer is discussed. Spectra with adequate signal/noise ratios can only be measured when the amplitude of the modulation is about equal to the half width at half height. Two parameters, the distance between the zero crossings and the ratio of the minimal and maximal excursions, may be fit to an empirical hypersurface to obtain values for the peak absorbance, the actual half width and the collision-broadened half width. Although the peak absorbance is not accurately calculated, the line widths appear to be calculated to at least the same accuracy that can be obtained from the single-beam absorption spectrum.
TL;DR: In this paper, the oxygen 2p and 2s levels for oxygen chemisorbed on a Pt 6(111) × (100) crystal were located −6 eV with a FWHM of 3 eV and the 2s at −21 eV.
TL;DR: Sixty percent single pass second-harmonic power conversion efficiencies were reported in Te pumped with a 12.8 μm NH 3 laser source in pulses of about 1 ns full width at half maximum.
TL;DR: In this article, a picosecond flash technique was used to detect the Sn←S1 absorption of cis-and trans-stilbene, and the decay of the transient absorption was exponential with one component (110±10 ps), being same as the fluorescence decay at room temperature.
Abstract: Extremely intense and sharp Sn←S1 absorption of cis‐ and trans‐stilbene was observed with a picosecond flash technique. The decay of the transient absorption of trans‐stilbene was exponential with one component (110±10 ps), being same as the fluorescence decay at room temperature, and thus assigned to the Sn←S1 absorption. The molar coefficient of the absorption was 7×105 M−1 cm−1 with the full width at half maximum of 1×103 cm−1. The band width had a strong temperature dependence and became only 500 cm−1 at 77 K. A theoretical calculation, using a semiempirical Hamiltonian of PPP type, was made to analyze the nature of this observed intense absorption, and was found that the character of the transition was of the charge‐resonance among the ethylenic and two phenyl moieties in stilbene.