Al激光等离子体Stark加宽光谱观测

用YAG脉冲激光器产生的1.06μm激光,在高真空下轰击Al靶,观测到9条AlⅠ,AlⅡ和AlⅢ的等离子体谱线。利用高分辨率双光栅单色仪和光学多道分析仪(OMA),对谱线的Stark加宽和线型进行了测量。得到Al等离子体的电子密度沿靶面法向的分布,测得电子密度在1.0×l017～1.l×l018cm-3范围。利用谱线峰值法估算了等离子体的温度约为1.5×l05K。测量结果与半经典理论的计算基本符合     

Dynamics of inhomogeneous broadening of fluorescence spectra of dye solutions

Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 49, No. 1, pp. 40–45, July, 1988.     

Impurity absorption spectroscopy in 28Si: the importance of inhomogeneous isotope broadening

We report high-resolution infrared absorption spectra of the neutral donors phosphorus and lithium, and the neutral acceptor boron, in isotopically pure 28Si crystals. Surprisingly, many of the transitions are much sharper than previously reported in natural Si. In particular, the 2p(0) line of phosphorus in 28Si has a full width at half maximum of only 4.2 microeV, about 5 times less than the narrowest 2p(0) line previously reported for natural Si, making it the narrowest shallow impurity transition yet observed. The widely held assumptions that the impurity transitions previously reported in high quality samples of natural Si revealed the true, homogeneous linewidths, are thus shown to be incorrect. The sharper transitions in 28Si also reveal new substructures in the boron and lithium spectra.     

Stark broadening and shift of fluorine I lines

Stark widths and shifts of some prominent F I spectral lines have been determined experimentally in aZ-pinch plasma in dichlorodifluoromethane on a shot-to-shot basis. The electron density was determined by the laser interferometry while the electron temperature was measured from relative intensities of Cl II lines. Temperatures were in the range 19100–36200 °K; electron densities varied from 0.71 to 1.43×10¹⁷cm^?3. Measured F I linewidths and shifts are compared with theoretical results computed by Griem and it is shown that a) experimental widths are systematically smaller and the degree of discrepancy increases with temperature, b) line shifts are also smaller than theoretical with exception of multiplets 5 and 6 with the shifts of opposite sign than theoretically predicted, c) experimental shift-to-width ratios decrease with the temperature but less than theoretically expected. Attention is drawn in general, to the systematic discrepancy between experimental results for neutral atom lines and the theory. The magnitude of this disagreement is related to the relative position of the energy levels of spectral line to the ionisation limit.     

Stark broadening and displacement of isolated He I lines

Experimental results for Stark broadened He I lines emitted by a helium plasma jet (N_e≈3×10¹⁶ cm^-3) are compared with theory; agreement is well enough for widths whereas shifts calculations present generally large discrepancies with experimental data.     

Migration of electronic excitation energy in heterogeneous media under conditions of inhomogeneous broadening of energy levels

Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 54, No. 6, pp. 919–922, June, 1991.     

Stark broadening of singly ionized strontium and calcium lines

Profiles of five calcium II and six strontium II lines have been measured in an argon plasma behind the reflected shock wave. The plasma was produced in an electromagnetically drivenT tube and calcium and strontium were present as an impurities. Electron densities were in the range 1.91–3.40·10¹⁷ cm^?3 and the electron temperatures between 10300 and 14200 °K. The half halfwidths of the measured profiles of some Ca II and Sr II multiplets show large discrepancies with theoretical predictions.     

Linear Stark effect in spectroscopy and luminescence of doped inorganic insulating crystals

The various effects in spectroscopic and luminescent properties of doped inorganic insulating crystals connected with the linear Stark effect (LSE) in the spectra of inversionless impurity centers are systematized. The phenomena connected with both the LSE in a uniform external electric field and in internal Coulomb fields of charged defects in crystal lattices are discussed. These include: the pseudo-Stark splitting (PSS) in the spectra of transition metals and rare-earth ions in an external field; the PSS in the spectra of impurity ions induced by a ferroelectric phase transition; the drastic shift of photoionization thresholds of ions in multisites; the off-resonant persistent hole-burning in the zero-phonon lines of inversionless centers; and the photoelectric anomalies of optically excited ruby.     

Stark broadening of visible neutral helium lines in a plasma

Side-on observations of the visible spectrum emitted by a helium plasma generated in a wall-stabilized arc are reported. Electron densities range from 0.2 to 1.3 × 10²²m^-3 and electron temperatures vary from 10,000 to 20,000 K. Most of the seventeen measured lines are “isolated” at the conditions of the experiment. Here, “isolated” refers to quantum levels which are non-degenerate even in the presence of perturbing fields. Electron densities derived from the Stark-widths of the isolated lines agree to within 15% of the values determined from Hβ and from the quasi-degenerate He(I) lines at 4471 and 4921 Å. Similar agreement is observed for the static-ion Stark broadening parameters. However, at the conditions of this experiment, the static-ion approximation is not valid near the center of some of the isolated lines. The observation of ion-dynamic effects in neutral isolated lines is reported here for the first time. In the isolated lines, the measured ion-dynamic effects are reasonably consistent with calculations based on an adiabatic “unified” theory for the ion perturbers. A simple parametric expression closely approximates the ion-dynamic contribution to the half-width of isolated lines. Hydrogenic (non-isolated) neutral helium lines exhibit a large discrepancy with theoretical profiles near the line center, where ion-dynamic effects are important.     

Stark broadening of isolated spectral lines of heavy elements in plasmas

In this paper, we present results of semiclassical calculations of Stark broadening parameters for some lines of heavy neutral atoms. Comparisons with experiment show large discrepancies previously undetected for lighter elements. Critical evaluation of experimental data indicate that in most cases the experiment must be blamed for these discrepancies.     

Many-body effect in Auger-photoelectron coincidence spectroscopy spectra

When the shakeup/down excitations are not negligible in the core-level electron ionization, the photoelectron spectral peak measured in coincidence with a selected singles (noncoincidence) Auger-electron spectral peak does not necessarily coincide with the singles one. We discuss how the interference between the core-hole decay of a fully relaxed core-hole state and that of an incompletely relaxed one via the interaction between the final states created by the respective core-hole decays, affects the kinetic energy shift and asymmetrical lineshape change of the coincidence photoelectron spectrum compared to the singles one. When the final-state interaction is considerable, the interference reduces much the energy shift and the asymmetrical lineshape change. By the Auger-photoelectron coincidence spectroscopy (APECS) we can study the interference effect which does not manifest in the singles photoelectron spectrum. We discuss also the interference effect when the core-hole decay rates of both the fully relaxed core-hole state and the incompletely relaxed one depend critically on the changes in both the Auger-electron kinetic energy and the final-state potential. The effect is fairly independent of the changes.     

Mutual atomic effect in porphyrin molecules and its manifestation in their structure and electronic absorption spectra

The state of the art and trends in development of the concepts of the mutual atomic effect in molecules of porphyrins and organic and complex compounds are reported. The electronic effects of coordination in metalloporphyrin molecule and those of aza- and benzosubstitution in porphyrins-ligands are considered in the context of the chromophore-auxochrome theory. The particular role of the proton as the strongest auxochrome is noted. Reported at the VIIth International Conference on Spectroscopy of Porphyrins and Their Analogs, Minsk, September 22–26, 1998. Institute of the Chemistry of Solutions of the Russian Academy of Sciences, 1, Akademicheskaya Str., Ivanovo, 153045, Russia. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 4, pp. 483–487, July–August, 1999.     

Stark broadening and shift measurements of two doubly excited NI multiplets

Experimental Stark-broadening studies of two selected doubly excited NI multiplets from the infrared wavelength range are presented. One of them is very sensitive to interactions with charged particles in plasmas and the other exhibits — at the same plasma conditions — only very small broadening and shift. A high current wall-stabilized arc operated in helium with admixture of nitrogen and hydrogen was applied as the excitation source. The radiation of the plasma was detected by applying a grating spectrometer equipped with a CCD detector. Measurements were performed at electron densities of the plasma between 3×10¹⁵ and 7×10¹⁵ cm^-3, corresponding to temperatures from the range 8000–10500 K. Electron impact widths (w_e) and shifts (d_e) of fine structure components of these multiplets were determined. The evaluated Stark broadening parameters (w_e, d_e) are compared with other experimental data and with calculated Stark effect constants.     

Estimate of inhomogeneous line broadening in steady-state magnetic resonance

We have established relationships between the experimental and theoretical absorption and dispersion line parameters for steady-state magnetic resonance, allowing us to determine both the field characteristics (amplitude of the a.c. magnetic field) and the relaxation characteristics (longitudinal and transverse relaxation times) of the object under study.