Showing papers on "Doppler broadening published in 1998"
TL;DR: In this article, a grid of computed far and mid-ultraviolet spectra (850-2000 A) of the integrated light from steady-state accretion disks in luminous cataclysmic variables is presented.
Abstract: We present a large grid of computed far- and mid-ultraviolet spectra (850-2000 A) of the integrated light from steady-state accretion disks in luminous cataclysmic variables. The spectra are tabulated at 0.25 A intervals with an adopted FWHM resolution of 1.0 A, so they are suitable for use with observed spectra from a variety of modern space-borne observatories. Twenty-six different combinations of white dwarf mass M(sub wd) and mass accretion rate dot-m are considered, and spectra are presented for six different disk inclinations i. The disk models are computed self-consistently in the plane-parallel approximation, assuming LTE and vertical hydrostatic equilibrium, by solving simultaneously the radiative transfer, hydrostatic equilibrium, and energy balance equations. Irradiation from external sources is neglected. Local spectra of disk annuli are computed taking into account line transitions from elements 1-28 (H through Ni). Limb darkening as well as Doppler broadening and blending of lines are taken into account in computing the integrated disk spectra. The radiative properties of the models are discussed, including the dependence of ultraviolet fluxes and colors on M(sub wd), dot-m, and i. The appearance of the disk spectra is illustrated, with regard to changes in the same three parameters. Finally, possible future improvements to the present models and spectra are discussed.
134 citations
TL;DR: In this paper, the Rautian-Sobelman approach describing the collision-Doppler shape of spectral line that takes into account both soft and hard velocity-changing collisions is extended to the case when correlation between Doppler and collision broadening as well as the dispersion line asymmetry should be considered.
Abstract: The Rautian-Sobelman approach describing the collision-Doppler shape of spectral line that takes into account both soft and hard velocity-changing collisions is extended to the case when correlation between Doppler and collision broadening as well as the dispersion line asymmetry should be considered. Numerical calculations show that speed-dependent effects can produce the additional line narrowing as well as broadening and also the line asymmetry. It is shown that speed-dependent profiles based on the soft and hard collision models differ much more one from another than those which omit the speed-dependent effects.
131 citations
TL;DR: Experimental results from hole-burning, single-molecule, photon echo, and resonance Raman and fluorescence studies are focused on, and the role of coupling of solvent phonons to the solute's electronic transition is stressed.
Abstract: The magnitudes, time scales, and underlying mechanisms responsible for broadening the electronic spectra of molecules in liquid solutions and glasses are reviewed. The emphasis is on experimental results from hole-burning, single-molecule, photon echo, and resonance Raman and fluorescence studies. The influence of the time scale of the measurement in distinguishing between homogeneous broadening (electronic dephasing) and inhomogeneous broadening is discussed, and the role of coupling of solvent phonons to the solute's electronic transition is stressed.
126 citations
TL;DR: In this paper, photoionization models accounting for both photoelectric and resonant absorption lines between 0.1 and 10 keV are presented, without requiring relativistic outflowing velocities of the gas, if the physical properties of these absorbers are close to those found in flat X-ray spectrum Seyfert 1 galaxies.
Abstract: We present photoionization models accounting for both photoelectric and resonant absorption. Resonance absorption lines from C, O, Ne, Mg, Si S and Fe between 0.1 and 10 keV are treated. In particular we consider the complex of almost 60 strong Fe L absorption lines around 1 keV. We calculate profiles, intensities and equivalent widths of each line, considering both Doppler and natural broadening mechanisms. Doppler broadening includes a term accounting for turbulence of the gas along the line of sight. We computed spectra transmitted by gas illuminated by drastically different ionizing continua and compared them to spectra observed in flat X-ray spectrum, broad optical emission line type 1 AGN, and steep X-ray spectrum, narrow optical emission line type 1 AGN. We show that the $\sim 1$ keV absorption feature observed in moderate resolution X-ray spectra of several Narrow Line Seyfert 1 galaxies can be explained by photoionization models, taking into account for resonance absorption, without requiring relativistic outflowing velocities of the gas, if the physical properties of these absorbers are close to those found in flat X-ray spectrum Seyfert 1 galaxies.
82 citations
TL;DR: In this paper, an absorption feature at ~37 keV, which is attributable to electron cyclotron resonance, has been discovered in the low-mass X-ray binary 4U 1626-67 performed during the BeppoSAX science verification phase.
Abstract: We report on an observation of the low-mass X-ray binary 4U 1626-67 performed during the BeppoSAX science verification phase. An absorption feature at ~37 keV, which is attributable to electron cyclotron resonance, has been discovered in its pulse-averaged spectrum. The inferred neutron star magnetic field strength is 3.2(1+z)×1012 G, where z is the gravitational redshift. The feature is deep and narrow and is resolved in both the broadband fit and in the ratio of observed counts to those seen from the Crab pulsar. The cyclotron resonance energy is in good agreement with the empirical relation between cyclotron energy and high-energy cutoff, while its width is in agreement with the expected Doppler broadening of thermal electrons at the cyclotron resonance frequency. The broadband 0.1-200 keV spectrum is well fit by a two-component model: a 0.27±0.02 keV blackbody and a power law with a photon index of 0.89±0.02. This is the first broadband observation made after the change from spin-up to spin-down that occurred in mid-1990: it confirms the harder spectrum with respect to those observed in the 2-10 keV range.
80 citations
TL;DR: In this paper, a gas-filled hollow fiber and chirped mirrors with high-energy 20-fs input pulses were used for spectral broadening and ultrabroad-band dispersion control.
Abstract: Powerful techniques for spectral broadening and ultrabroad-band dispersion control, which allow compression of high-energy femtosecond pulses to a duration of a few optical cycles, are analyzed. Spectral broadening in a gas-filled hollow fiber and compression by chirped mirrors with high-energy 20-fs input pulses are presented. Using 1-mJ seed pulses we have demonstrated the generation of 0.5-mJ 5-fs pulses at 0.8-/spl mu/m and 1-kHz repetition rate. General design criteria to scale the compression technique toward the terawatt level are presented.
77 citations
TL;DR: In this paper, an ultrasonic constant-beamwidth transducer system which is capable of generating an extended focal zone by electronically focusing the beam over the desired water-depth range is described.
Abstract: An ultrasonic constant-beam-width transducer system which is capable of generating an extended focal zone by electronically focusing the beam over the desired water-depth range is described Beam directivity measurements show that the higher beam directivity and the reduction in side-lobe level lead to an increase of the signal-to-noise ratio by up to 15 dB compared with that of a plane disc transducer It also allows one to attain a significant reduction of undesirable spectral broadening effects which in the case of plane disc transducers lower the final resolution and interfere with the correct interpretation of data Using the focalized transducer, simultaneous 3D velocity component profile measurements over the whole water depth are carried out in uniform, open-channel flow and reveal the presence of coherent structures In the transversal direction, a stationary secondary current composed of two stationary vortices is observed Compared with a plane disc transducer system, the focalized system increases the resolution by up to 50%
77 citations
TL;DR: In this paper, an absorption feature at � 37 keV, attributable to electron cyclotron resonance, has been discovered in the pulse averaged spectrum of the low-mass X-ray binary 4U1626-67 performed during the BeppoSAX Science Verification Phase.
Abstract: We report on an observation of the low-mass X–ray binary 4U1626–67 performed during the BeppoSAX Science Verification Phase. An absorption feature at � 37 keV, attributable to electron cyclotron resonance, has been discovered in its pulse averaged spectrum. The inferred neutron star magnetic field strength is 3.2 · (1 + z) × 10 12 G, where z is the gravitational redshift. The feature is deep and narrow and is resolved in both the broad-band fit and in the ratio of observed counts to those seen from the Crab. The cyclotron resonance energy is in good agreement with the empirical relation between cyclotron energy and high energy cutoff, while its width is in agreement with the expected Doppler broadening of thermal electrons at the cyclotron resonance frequency. The broad-band 0.1–200 keV spectrum is well fit by a two-component model: a 0.27 ± 0.02 keV blackbody and a power law with a photon index of 0.89 ± 0.02. This is the first broad-band observation made after the change from spin-up to spin-down that occurred in mid 1990: it confirms the harder spectrum with respect to those observed in the 2–10 keV range.
74 citations
TL;DR: Positron annihilation lifetime and Doppler broadening of annihilation radiation experiments are performed in a polyurethane film using the mono-energetic slow positron probe as a function of positron energies.
Abstract: Positron annihilation lifetime and Doppler broadening of annihilation radiation experiments are performed in a polyurethane film using the mono-energetic slow positron probe as a function of positron energies. Significant variations of positron annihilation signals are observed at a short distance from the surface . The ortho-positronium lifetime in the polymer increases near the surface, while its intensity decreases. The intensity results are consistent with the description of a free-volume hole model for positronium formation proposed by Brandt, Berko and Walker. This study further confirms that positron annihilation spectroscopy is a sensitive probe for the characterization of physical properties of sub-nanometre defects, such as free volumes and holes for polymeric materials.
64 citations
TL;DR: In this article, the thermalization of positronium (Ps) formed at a few eV in gases was investigated using time-resolved, Doppler broadening measurements of the annihilation photons.
Abstract: The thermalization of positronium (Ps) formed at a few eV in gases is investigated using time-resolved, Doppler broadening measurements of the annihilation photons. Magnetic quenching permits energy measurements about 40 ns after Ps is formed in ${\mathrm{H}}_{2}$, ${\mathrm{N}}_{2}$, He, Ne, Ar, isobutane, and neopentane. The thermalization rate is measured by changing the gas density, and a classical elastic scattering cross section and a Ps formation energy are determined. The impact of Ps thermalization on decay rate experiments using gases is also discussed.
63 citations
TL;DR: In this article, the physics of polarization spectroscopy were investigated by direct numerical integration of the time-dependent density matrix equations and the Zeeman structure of the upper and lower energy levels was included in a multistate formulation of the density matrix equation.
Abstract: The physics of polarization spectroscopy (PS) is investigated by direct numerical integration of the time-dependent density matrix equations. The Zeeman structure of the upper and lower energy levels is included in a multistate formulation of the density matrix equations. The numerical solution of the time-dependent density matrix equations enables us to investigate the effects of strong saturation on PS signal levels and line shapes. Bath levels not directly coupled by the laser radiation are included in the numerical modeling to investigate the effects of collisional rates and different types of collisions on signal levels and line shapes. The effects of Doppler broadening are included by solving the density matrix equations for numerous velocity groups. At low laser power we find that the homogeneously broadened PS line shape is Lorentzian-cubed, as compared to the Lorentzian predicted in several previous low-power analytical solutions. In the low laser power regime, the line-center PS signal is propor...
TL;DR: In this article, the authors studied the transfer efficiency of stimulated Raman scattering involving adiabatic passage (STIRAP) in a molecular beam and in the bulk of the NO molecule induced by the interaction of two delayed laser pulses.
Abstract: Coherent population transfer between vibrational levels of the NO molecule induced by the interaction of two delayed laser pulses, also referred to as stimulated Raman scattering involving adiabatic passage (STIRAP), is studied experimentally in a molecular beam and in the bulk. The consequences of hyperfine splitting and Doppler broadening are discussed in detail. Unlike in previous studies of this kind, transfer occurs simultaneously between more than one group of non degenerate levels. In a molecular beam or in the bulk, the transfer efficiency of STIRAP exceeds that obtained by Stimulated Emission Pumping (SEP) by a factor of 3.6 or 15, respectively. We estimate the absolute transfer efficiency T in the beam to be \(\), while \(\) is found in the bulk. In both cases, this is \(\) of the maximum value expected from numerical studies. Possible reasons for this discrepancy are discussed. Finally we show that the absorption of a pump pulse in a weakly absorbing medium is significantly enhanced by the presence of a copropagating Stokes pulse when the Rabi frequency \(\) of the latter is smaller than the width of the Doppler profile \(\). The relation of this observation to the phenomenon of Electromagnetically Induced Transparency (EIT), which is observed for \(\), is also discussed.
TL;DR: In this article, a spectral line shape model accounting for both the collisional confinement narrowing of the Doppler distribution and the inhomogeneous effects due to the speed dependence of collisional broadening and shifting parameters is proposed.
Abstract: A spectral line shape model accounting for both the collisional confinement narrowing of the Doppler distribution and the inhomogeneous effects due to the radiator speed dependence of the collisional broadening and shifting parameters is proposed. The velocity changes are assumed to be induced as well by hard as soft collisions. Doppler-collision correlations and speed-class exchanges are taken into account. A comparison with the previous models used for the Doppler regime and for the collisional one is done. The present model also applies for the intermediate regime where the two above mechanisms are simultaneously efficient. The spectral line shape characteristics are exemplified through the H2–Ar and C2H2–Xe prototype molecular systems.
15 Feb 1998-Philosophical transactions - Royal Society. Mathematical, physical and engineering sciences
TL;DR: Spectral densities for dye molecules in polar solutions are presented and discussed in terms of molecular models for the dynamics and the breakdown of the harmonic bath picture at low frequencies is presented.
Abstract: The origins of electronic spectral broadening in solutions, glasses and proteins are discussed via three pulse stimulated echo peak–shift measurements. Spectral densities for dye molecules in polar solutions are presented and discussed in terms of molecular models for the dynamics. The breakdown of the harmonic bath picture at low frequencies is presented. Finally, echo measurements on light harvesting complexes of purple bacteria are presented and it is shown that the energy transfer timescale can be obtained from peak–shift measurements.
TL;DR: In this paper, the Doppler profiles and positron lifetimes were measured and the local density enhancement of Puska, Seitsonen and Nieminen was analyzed.
Abstract: Enhancement due to positron-electron correlation has been studied in Al by calculating and measuring Doppler profiles and positron lifetimes. It is found that only the local density enhancement of Puska, Seitsonen and Nieminen can simultaneously reproduce the profile and the lifetime, but our analysis suggests that a GGA-type enhancement of reduced strength would likely give even better results.
TL;DR: In this article, the influence of the gas velocity on the discharge equilibrium in a low-pressure (1 Torr) microwave driven hydrogen plasma was investigated and it was shown that gas velocity has a great influence on the dissociation degree, the key parameter being the residence time of the molecules in the plasma with respect to their effective dissociation time.
Abstract: We report on the influence of the gas velocity on the discharge equilibrium in a low-pressure (1 Torr) microwave driven hydrogen plasma. We show that the gas velocity has a great influence on the dissociation degree, the key parameter being the residence time of the molecules in the plasma with respect to their effective dissociation time. The power balance (plasma length, electric field…) is substantially modified by the variations of the dissociation degree induced by the change in gas velocity. On the contrary, the gas temperature, determined by Doppler broadening of H atom Balmer lines, is not directly dependent on the gas velocity. Simple calculations confirm that the gas temperature is determined by local parameters and that heat is not axially transported. Surprisingly, dissociation of the H2 molecules does not seem to play any significant role for the heating of the gas.
TL;DR: It is shown that the self-pulsing emission can still be observed when the typical residual Doppler broadening of an atomic beam is taken into account.
Abstract: Lasing without inversion (LWI) in specific models of closed three-level systems is analyzed in terms of nonlinear dynamics. From a linear stability analysis of the trivial nonlasing solution of the homogeneously broadened systems with on-resonance driving and laser fields, we find that, near lasing threshold, resonant closed $\ensuremath{\Lambda}$ and $V$ schemes yield continuous-wave LWI while resonant cascade schemes can give rise to self-pulsing LWI. The origin of this different behavior is discussed. For parameters of a real cascade system in atomic ${}^{138}\mathrm{Ba}$ we check numerically that the self-pulsing solution is stable in a broad range of nonzero detunings. It is shown that the self-pulsing emission can still be observed when the typical residual Doppler broadening of an atomic beam is taken into account.
TL;DR: In this paper, a highly realistic Monte Carlo code is used to simulate radiation trapping including effects due to partial frequency redistribution and with a spectral line profile dominated by natural (radiative) broadening resonance collisional broadening and Doppler broadening.
Abstract: A highly realistic Monte Carlo code is used to simulate radiation trapping including effects due to partial frequency redistribution and with a spectral line profile dominated by natural (radiative) broadening resonance collisional broadening and Doppler broadening. Results from 294 simulations are used to determine the fundamental mode trapped decay rate in cylindrical geometry over a very wide range of parameter space including a factor of in gas density, a factor of 1000 in column radius, and a factor of 1000 in Doppler width. The fundamental mode decay rates are fitted to an analytical formula expressed in terms of three dimensionless parameters which can conveniently be applied to a variety of gases, column radii and Doppler widths.
TL;DR: In this paper, an ansatz that permits a treatment of the effects of Doppler broadening in the theory of intense steady-state pulse pairs propagating in three-level (ensuremath{\Lambda} or V) media is introduced.
Abstract: We introduce an ansatz that permits a treatment of the effects of Doppler broadening in the theory of intense steady-state pulse pairs propagating in three-level (\ensuremath{\Lambda} or V) media. We have derived analytic solutions for pulse amplitudes, for group and phase velocities, and for the probability amplitudes of the atoms in the transmission medium. The solutions are different for the \ensuremath{\Lambda} and V cases.
TL;DR: In this paper, the positron lifetime and Doppler broadening measurements of all the samples could be decomposed into three components having lifetimes around 200, 500, and 1800 ps.
Abstract: Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Calcutta 700 064, India~Received 16 July 1996; revised manuscript received 14 August 1997!Composites of silver particles of diameters in the range 16.4–33.3 nm and polyacrylamide were prepared bya chemical method. Positron lifetime and Doppler broadening measurements of these samples were carried out.The positron lifetime spectra of all the samples could be decomposed into three components having lifetimesaround 200, 500, and 1800 ps. These are believed to arise due to vacancy clusters on the grain surfaces, theopen spaces between the grain surface and the surrounding polymer layer and the annihilation of orthopositro-nium at the free-volume defects, respectively. The lifetime of positrons trapped at the grain surface defects andthe grain-polymer interface is found to decrease as the grain size is increased. Doppler broadening measure-ments were carried out from 13 K to 300 K on a silver-polyacrylamide nanocomposite containing silverparticles of diameters in the range 2–20 nm. The line-shape parameterS is decomposed by a mixture rule toobtain the contribution of electrons from the nanoparticles. This shows a sharp increase at around 80 K that isadduced as evidence for the splitting of the electron energy levels in the nanosized silver particles leading toa semiconductorlike behavior. @S0163-1829~98!03102-6#I. INTRODUCTION
TL;DR: Theory for Doppler effects in resonant x-ray Raman scattering (RXS) is presented in this article, where it is shown that the "electron" DoP effect is important in nonradiative RXS for decay transitions between conti...
Abstract: Theory for Doppler effects in resonant x-ray Raman scattering (RXS) is presented. It is shown that the "electron" Doppler effect is important in nonradiative RXS for decay transitions between conti ...
TL;DR: In this article, the effects of post-implantation annealing of damage in 6H-SiC caused by ion implantation at two different fluences have been studied by monoenergetic positron Doppler broadening and lifetime techniques.
Abstract: The effects of post-implantation annealing of damage in 6H-SiC caused by ion implantation at two different fluences have been studied by monoenergetic positron Doppler broadening and lifetime techniques. The measurements are supported by new calculations of positron lifetimes in vacancy clusters in SiC. At both fluences two defected layers are identified and characterized by depth and defect type as a function of annealing temperature. The results indicate that it is impossible to remove the radiation damage by annealing at temperatures up to .
TL;DR: In this article, the absorption spectra, fluorescence spectra and resonance Raman profiles of 4-dimethylaminophenyl-ethenyl]-1-methyl-pyridinium iodide (HR) were modeled using time-dependent wave packet theory and the Brownian oscillator solvent dephasing model.
Abstract: The spectroscopic properties of 4-[2-(4-dimethylaminophenyl)ethenyl]-1-methyl-pyridinium iodide (HR) in different solvents reveal the important effects of solvent dynamics on the spectral broadening and the intramolecular charge transfer of HR. In this article, Raman excitation profiles for 18 vibrational modes of HR are reported in aqueous solution at wavelengths that span the S0→S1 charge transfer transition. The absorption spectra, fluorescence spectra and resonance Raman profiles of HR are modeled using time-dependent wave packet theory and the Brownian oscillator solvent dephasing model. The solvent reorganization energy in the absorption process is much greater than that due to internal vibrational modes, and the solvent reorganization energy for the emission process is considerably smaller than that for the absorption process. The fluorescence spectrum is mainly broadened by the inhomogeneous Gaussian distribution of the electronic energy, perhaps due to internal rotations in the molecule. The resu...
TL;DR: In this article, the intensity smoothing of noisy optical signals with an SOA carries a penalty of spectral broadening (increased phase noise) that increases with increasing alpha parameter (linewidth enhancement factor).
Abstract: We present calculations of the intensity smoothing of stochastic light by a semiconductor optical amplifier (SOA). We predict spectral changes of the light that are due to amplitude-to-phase coupling in the gain medium. The intensity smoothing of noisy optical signals with an SOA carries a penalty of spectral broadening (increased phase noise) that increases with increasing alpha parameter (linewidth enhancement factor). The spectral broadening also increases with increasing strength of the intensity fluctuations being smoothed.
KEK1
TL;DR: Nelson et al. as discussed by the authors improved the treatment of low-energy photon transport in the EGS4 code by linearly polarized photon scattering, Doppler broadening of Compton-scattered photons, L-X-ray and L-photoelectron production and electron impact ionization.
TL;DR: In this paper, the spectral broadening due to fiber amplifier phase noise has been investigated experimentally, and the measured spectrum broadening reveal to be much smaller than expected, compared to previously published data.
Abstract: Spectral broadening due to fiber amplifier phase noise has been investigated experimentally. Results differ from previously published data. The measured spectral broadening reveal to be much smaller than expected.
TL;DR: In this article, a molecular beam epitaxy-grown microcavity light-emitting diodes with InGaAs/GaAs quantum wells and a hybrid top mirror are presented.
Abstract: Results on molecular beam epitaxy-grown microcavity light-emitting diodes with InGaAs/GaAs quantum wells and a hybrid top mirror are presented. An external quantum efficiency of 14.8% is achieved for a 400 μm diam light-emitting diode. The strong influence of the spectral overlap between the spontaneous emission spectrum and the cavity resonance mode on the radiation pattern is shown. The angular emission profile is compared with model predictions for different detunings, and a very good agreement is obtained when the asymmetric spectral broadening of the intrinsic spontaneous emission is taken into account.
TL;DR: In this paper, the effects of collisional dephasing and Doppler broadening on the quantum beats, narrow resonances, and probe transparency induced by quantum interference in a Vee-type atom consisting of an excited doublet coupled to a single ground level by the vacuum were investigated.
Abstract: We investigate the effects of collisional dephasing and Doppler broadening on the quantum beats, narrow resonances, and probe transparency induced by quantum interference in a Vee-type atom consisting of an excited doublet coupled to a single ground level by the vacuum. We show that the amplitudes of the quantum-beat oscillations are greatly reduced, and the narrow resonances are substantially suppressed and broadened, for even very small dephasing rates and Doppler broadening. Fluorescence quenching and the previously reported probe transparency can never occur in the presence of dephasing collisions and Doppler broadening.
TL;DR: In this paper, the general conditions and limitations for the realization of frequency up-conversion via lasing without inversion (LWI) were analyzed and a class of schemes in which LWI can be achieved via optical- or microwave-frequency driving on a weakly allowed transition was proposed.
Abstract: We analyze the general conditions and limitations for the realization of frequency up-conversion via lasing without inversion (LWI). Based on this analysis we propose a class of schemes in which LWI can be achieved via optical- or microwave-frequency driving on a weakly allowed transition. A noninversion amplification process based on this system is studied with particular emphasis on propagation effects and Doppler broadening. Amplification of both monochromatic and bichromatic fields is considered and a possible implementation in realistic atoms and ions is discussed.
TL;DR: In this article, the results of experimental determinations of the gas temperature and plasma parameters in a microwave discharge not at thermal equilibrium are presented, where the interaction of the excited atoms and molecules with heavy particles is considered.
Abstract: Results of experimental determinations of the gas temperature and plasma parameters in a microwave discharge not at thermal equilibrium are presented. The investigation is concerned with high-pressure hydrogen under conditions such that radiation is emitted both by atomic and by molecular components of the plasma are primarily governed by the interaction of the excited atoms and molecules with heavy particles. Because this takes place the approximate models which are successfully applied to analyse data from spectroscopic diagnostics cannot be used to describe the radiative properties of the discharge. One of the main objectives of research consists of making headway in spectral methods of gas-temperature determination in the high pressure range by invoking for interpretation of experimental data calculations performed in the framework of the kinetic scheme of thermal non-equilibrium discharge in hydrogen as well as general physical reasoning relating to the role of interactions between heavy particles in non-equilibrium plasma radiation. The following measurement techniques have been used: spectral measurements of Balmer-series radiation; spectral measurement of the gas temperature by recording the Doppler broadening of the ; and spectral measurements of by recording the Fulcher band. In addition the electron concentration has been measured with the help of a microwave interferometer and pyrometric measurements of the temperature of a test solid body placed in a microwave-discharge plasma have been performed. Measurements of the gas temperature agree satisfactorily under the assumption that collisions of excited particles with heavy components of a gas-discharge medium are of considerable importance. Conclusions regarding the ion composition and degree of dissociation of hydrogen molecules can be drawn.