RESUMO
Optical frequencies of the D lines of (6,7)Li were measured with a relative accuracy of 5 × 10⻹¹ using an optical comb synthesizer. Quantum interference in the laser induced fluorescence for the partially resolved D2 lines was found to produce polarization dependent shifts as large as 1 MHz. Our results resolve large discrepancies among previous experiments and between all experiments and theory. The fine-structure splittings for 6Li and 7Li are 10052.837(22) MHz and 10053.435(21) MHz. The splitting isotope shift is 0.599(30) MHz, in reasonable agreement with recent theoretical calculations.
RESUMO
We describe the use of phosphor image plates for recording spectra in the vacuum ultraviolet (VUV) and for determining accurate relative and absolute intensities. We investigated the spatial uniformity, noise, linearity of the response to VUV light, fading characteristics, saturation characteristics, reproducibility of the image when scanned multiple times, and long-term stability and lifetime of the plates. We find that the plates have a linear intensity response with a dynamic range of more than 4 orders of magnitude. We also show that they have potential as an absolute detector for VUV radiation.
RESUMO
Recent observations at the National Institute of Standards and Technology indicate that the Ar I wavenumbers reported by Whaling et al. [J. Res. Natl. Inst. Stand. Technol. 107, 149 (2002)] are systematically too large. To investigate the source of this problem, selected lines of Ar I and Ar II were remeasured in the same spectra used by Whaling et al. The measurements show that the Ar I wavenumbers of Whaling et al. are systematically shifted with respect to the Ar II wavenumbers previously reported by Whaling et al. [J. Quant. Spectrosc. Radiat. Transfer 53, 1 (1995)] based on the same spectra. The Ar I wavenumbers can be corrected by a constant multiplicative correction of 0.999 999 933.
RESUMO
We have observed the spectrum of neutral neon (Ne I) emitted by a microwave-excited electrodeless discharge lamp with the National Institute of Standards and Technology 2 m Fourier transform spectrometer. The spectra cover the regions 6929 Å to 11 000 Å with a resolution of 0.01 cm(-1) and 11 000 Å to 47 589 Å with a resolution of 0.007 cm(-1). We present a line list that includes more than 650 classified lines and provides an accurate and comprehensive description of the infrared spectrum. The response of the Fourier transform spectrometer was determined by using a radiometrically calibrated tungsten strip lamp, providing relative intensities that for moderate to strong lines are accurate to approximately 10 % over the entire range of the observations. The identities of many lines that were previously multiply classified are unambiguously resolved.
RESUMO
The spectrum of a platinum hollow-cathode lamp containing neon carrier gas was recorded photographically and photoelectrically with a 10.7 m normal-incidence vacuum spectrograph. Wavelengths and intensities were determined for about 5600 lines in the region 1130-4330 Å. An atlas of the spectrum is given, with the spectral lines marked and their intensities, wavelengths, and classifications listed. Lines of impurity species are also identified. The uncertainty of the photographically measured wavelengths is estimated to be ± 0.0020 Å. The uncertainty of lines measured in the photoelectric scans is 0.01 Å for wavelengths shorter than 2030 Å and 0.02 Å for longer wavelengths. Ritz-type wavelengths are given for many of the classified lines of Pt II with uncertainties varying from ±0.0004 to ± 0.0025 Å. The uncertainty of the relative intensities is estimated to be about 20%.
