Experimenteller Nachweis des H?-Leuchtens

Small free negative ions

“…The first was Wildt's attribution of a "missing factor" in the infrared opacity of the sum to photodetachment from H-. 22 We can trace a major stream in the study of negative ions from Wildt's work; it was followed by laboratory studies of luminosities of ionized gases in arcs and shocks in the Kiel laboratory of Lochte-Holtgreven, beginning with Lochte-Holtgreven's own study of H_ in arcs, 23 and by later work on H~in arcs24- 28 and shocks,29 and on O-,80 N-,81 and on Cl-32 in arcs. The existence of N~was also inferred from optical measurements of shocks.83 The astrophysical interest in photodetachment was one of the major stimuli, apparently, for the development of the crossed-beam method when the initial work was carried out on photodetachment from -.8•84…”

Sonoluminescence: how bubbles glow

“…Such discharges were previously shown to be associated with electron temperatures of 20 000-30 000 K and plasma densities of up to 10 26 electrons per m 3 [136,137]. These authors believe that during the expansion and the major part of the collapse, a levitating bubble is given by the Rayleigh-Plesset dynamics, as in equation (1).…”

“…For example, at temperatures of 2800-3000 K a band system near 4160 cm ¡1 was reported and identi ed as the collision-induced fundamental band of H 2 [102]; in the same study, at temperatures just slightly higher, a strong continuum was observed (but not explained) that extended well into the visible. Similar continua have often been cultivated to study radiative attachment (formation of H ¡ and O ¡ [136,137]), but in too many other cases the continua remained unexplained, even if some simple justi cation for the neglect, such as the black body spectra of glowing particles (soot), could not be given. However, there can be no doubt that radiative collisions of the types mentioned in sections 2.4.2 and 4.1 do contribute to the observable emission of such continua and, we think, probably also to the emission of sonoluminescence, speci cally also to multiple bubble elds.…”

“…high-powered jet and rocket engines, explosions, oxy-hydrogen detonations, and high-powered industrial furnaces [184][185][186]; shock wave studies [187,188]; and capillary spark and arc discharges [76,105,136,137]. Under such conditions temperatures of several thousand degrees, up to several tens of thousand degrees, have been reported, often combined with fairly high neutral densities.…”

“…(4) Radiative attachment. Negative ions, such as H ¡ [76,105,136,137] and O ¡ [75,201,202], absorb light very eYciently. The inverse reaction, radiative attachment, is therefore an important contributor to the emission spectra whenever negative ions may be formed [188,203].…”