Doppler spectroscopy results

Starting with the pioneering work [52] Doppler-free two-photon laser spectroscopy was also applied for measurements of the gross structure interval in mnoninm. Experimental results [52, 53, 54, 55] are collected in Table 12.5, where the error in the first brackets is due to statistics and the second error is due to systematic effects. The highest accuracy was achieved in the latest experiment [55]... 

For many years, this hydrogen maser measurement remained the most accurate experiment in modern physics. Only recently the accuracy of the Doppler-free two-photon spectroscopy achieved comparable precision [34] (see the result for the IS — 2S transition frequency in (12.7)). 

First,one important result of the infrared molecular spectroscopy is a discovery of stationary CO layer in Mira type variable star x Gyg, in which CO lines that stay stationary have been clearly separated from the photospheric CO lines that show cyclic Doppler-shifts by the large amplitude pulsation of the photosphere in time series spectra( Hinkle, Hall, Ridgway, 1982). It was suggested that the stationary CO layer may be located at several stellar radii above the stellar surface, since excitation temperature of the stationary CO layer of x Cyg was found to be 800K. 

As shown by Fig. 14.15, the resonances occur near zero field, and it is easy to calculate the small Stark shifts with an accuracy greater than the linewidths of the collisional resonances. As a result it is straightforward to use the locations of the collisional resonances to determine the zero field energies of the p states relative to the energies of the s and d states. Since the energies of the ns and nd states have been measured by Doppler free, two photon spectroscopy,22 these resonant collision measurements for n = 27, 28, and 29 allow the same precision to be transferred to the np states. If we write the quantum defect dp of the K np states as... 

Abstract. Using Doppler-tuned fast-beam laser spectroscopy the ls2p 3Po - 3Pi fine structure interval in 24Mg10+ has been measured to be 833.133(15) cm-1. The calibration procedure used the intercombination ls2s 1So - ls2p 3Pi transition in 14N5+. The result tests quantum-electrodynamic and relativistic corrections to high precision calculations, which will be used to obtain a new value for the fine structure constant from the fine structure of helium. 

The line widths in vibrational spectroscopy are a function of the measuring conditions and of the state of the sample. The natural line width of about 10 cm is not usually re.solved. The Doppler effect at room temperature contributes 10 cm. The contribution due to impacts and intermolecular interactions for a gas at 1 mbar is 10 cm and for 1 bar it is 10 cm. The resulting line width in the spectra of crystals is of the order 1 - 5 cm and for a liquid it may reach 20 cm. ... 

The original Acoustosizer used a single frequency whereas a later development has a range of 13 frequencies between 0.3 and 13 MHz. This allows the measurement of the dynamic mobility spectrum and the determination of the zeta potential and particle size. In order to invert the mobility spectrum into a size distribution a log-normal distribution of particle size is assumed. A comparison with photon correlation spectroscopy for determining particle size and laser Doppler anemometry for particle charge eonfirmed the results using ACS [266]. These and additional sedimentation measurements confirmed that changes in particle size and zeta potential due to dilution effects are likely to occur in aqueous and non-stabilized systems. 

Multiphoton resonant processes with simplest fundamental quantum systems exposed to sufficiently strong laser fields attracted conspicuous attention over last years. Currently, this interest is being especially strongly stimulated by dramatic improvements in the precision of measurements presently attainable in spectroscopic experimental studies of hydrogenic and few-particle atoms. Using methods of ultra high precision Doppler-free spectroscopy, particularly impressive results have been recently obtained in studies of fundamental bounded systems such as hydrogen (H) and its natural isotopes deuterium (D) and tritium (T) [1,2,3,4,5,6,7], positronium [8,9], denoted Ps = (e+ — e ), muonium [10,11,9,12,13,14,15], denoted (M = — e ), and the helium atom (He) [16[... 

Efforts to determine Neptune s rotation period from Earth-based observations using spectroscopy to find it from Doppler shifts of spectral lines across Neptune s disk and searches for periodic brightness changes gave conflicting and almost always incorrect results. 

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