The Extreme Ultraviolet Spectra of Ne IV, V and VI

Abstract

An electrical discharge suitable for the excitation of high stages of ionization in gases has been developed. This discharge has been used to excite neon gas and the resulting emission has been recorded with a 3-meter grazing incidence vacuum spectrograph. One hundred and seventeen lines have been identified in the spectrum of Ne IV; fifty-six lines in Ne V, and twenty-five in Ne VI. It has been possible to make fairly accurate calculations of the ionization potentials of Ne IV and Ne V as 96.43 volts and 125.8 volts, respectively. The ionization potential of Ne VI is estimated to be 157 volts.

Extension and new level optimization of the Ne IV spectrum

“…This procedure required knowledge of the spontaneous emission rates, which were calculated in the parametric fitting procedure using Cowan's codes [31]. The intensity values for the lines measured in the present work roughly correspond to the S/N multiplied by a factor of 100, with the exception of several lines with wavelengths longer than 357 Å, all originating from the 2s2p 4 configuration, for which the intensity values were derived from the observations of Lindeberg [9] and Paul and Polster [7]. These lines were anomalously weak (by about two orders of magnitude) on our spectrograms, as compared to other observations.…”

“…It is interesting to note that observed intensities of the lines originating from the 2p 5 2 P • levels (at 602.985, 605.594, 606.510 and 609.164 Å) in the experiment of Gallardo et al [25,28], relative to the neighboring lines from 2s 2 2p 2 ( 3 P)4p, 4d and 5s, were two orders of magnitude lower than that in other discharge light sources [7,8]. No trace of these lines was detected in our Penning discharge spectra.…”

“…The fine structure of the ground configuration 2s 2 2p 3 was established by Kramida et al [1] based on astrophysical observations [3,5,7] of parity-forbidden transitions within this configuration. Young et al [29] recently re-measured the 2s 2 2p 3 4 S • -2 P, 2 D lines in the far ultraviolet region.…”

A high efficiency ultrahigh vacuum compatible flat field spectrometer for extreme ultraviolet wavelengths

“…Shown in Figure 8 are the differences between the synthetic and standard wavelengths from the reported values (λ syn -λ rep and λ std -λ rep ) for the 35 identified lines [30][31][32][33][34][35][36][37][38][39]. The standard deviations of the differences are 0.011 nm and 0.008 nm respectively.…”

Review of methods for the excitation of atomic and ionic spectra by means of high-frequency discharges and sliding sparks

“…The hollow aluminum electrodes wer e connected to the coil . In one of his papers on the spark spectra of neon , de Bruin [1] reports that the highest intensity was obtained in the cfLpillary at a rather hi gh pressure, n amely 2 cm H g. The followin g ionization s tages h ave been attained : NevI [4], AI" IV [5], ler IV [6], Xe IV [7] . The association of t he various lines of a spectrum with t he different ionization stages may be done by variation of t he charging voltage and the inductance.…”