Doppler spectroscopy experimental

Baskin, J.S., Felker, P.M. and Zewail, A.H. (1987). Purely rotational coherence effect and time-resolved sub-Doppler spectroscopy of large molecules. II. Experimental, J. Chem. Phys., 86, 2483-2499. 

This chapter is concerned with experimental investigations of the dynamics of the dissociation of polyatomic neutral molecules carried out by the technique of laser Doppler spectroscopy, in bulk and under crossed-beam condition. Photodissociation is a basic process in the interaction of light with molecules, of interest in itself as an elementary molecular process and also with respect to a variety of applications in different fields. The interest has increased considerably in recent years, first, because the experimental investigation of photodissociation is rapidly advancing by the use of the laser, and second, because the laser makes possible to achieve photodissociation, state, and isotope selectively, by new excitation mechanisms. These are, aside from the common one-photon absorption, stepwise... 

Fig. 4.5 Experimental setup for sub-Doppler spectroscopy in a collimated molecular beam. Photomultiplier PMl monitors the total undispersed fluorescence, while PM2 behind a monochromator measures the dispersed fluorescence spectrum. The mass-specific absorption can be monitored by resonant two-color two-photon ionization in the ion source of a mass spectrometer...

Figure 10.2 shows a typical experimental arrangement for sub-Doppler spectroscopy in molecular beams. The photomultiplier PM 1 monitors the total fluorescence Ip- (XL) as a function of the laser wavelength (excitation spectrum, see Sect.8.2), whereas PM 2 records the dispersed fluorescence spectrum excited at a fixed laser wavelength, where the laser is stabilized... 

Accuracy of the radiofrequency measurements of the classic 2S — 2P Lamb shift [15, 16, 23, 24, 25] is limited by the large (about 100 MHz) natural width of the 2P state, and cannot be significantly improved. New perspectives in reducing the experimental error bars of the classic 2S — 2P Lamb shift were opened with the development of the Doppler-free two-photon laser spectroscopy for measurements of the transitions between the energy levels with different principal quantum numbers. Narrow linewidth of such transi-... 

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]... 

The methods described in this book are primarily concerned with the measurement of the microstructure of complex fluids subject to the application of external, orienting fields. In the case of flow, it is also of interest to measure the kinematics of the fluid motion. This chapter describes two experimental techniques that can be used for this purpose laser Doppler velocimetry for the measurement of fluid velocities, and dynamic light scattering (or photon correlation spectroscopy) for the determination of velocity gradients. 

Most precision spectroscopy of medium Z ions has been conducted at accelerators or tokamak plasmas, but the recent development of the electron beam ion trap (EBIT) has offered a new spectroscopic source to experimenters. Our experimental method takes advantage of the Doppler free and relatively clean spectra produced by an EBIT and is coupled with an external calibration source to allow absolute measurement of highly charged ions. These are the first precision X-ray measurements conducted at the NIST EBIT [12],... 

Fig 6 Two experimental arrangements for demonstrating the quality of an FM spectrum a) sum frequency generation in a nonlinear crystal followed by mode analysis of the generated ultraviolet b) Doppler-free two-photon spectroscopy. 

A broad overview of traditional methods and recent developments in experimental positron spectroscopy is presented. A discussion of the generation and detection of positrons and their annihilation radiation is followed by a survey of techniques used for positron lifetime measurement, Doppler broadening spectroscopy and angular correlation of annihilation radiation, and the opportunities presented by combining these methods (e.g. in age-momentum correlation) and/or extending their capabilities by the use of monoenergetic positron beams. Novel spectroscopic and microscopic techniques using positron beams are also described. 

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[... 

The photodissociation cross sections and angular distributions can be obtained experimentally by different methods for example, time of flight (TOF) photofragment translational spectroscopy (Busch, et al., 1969), Doppler analysis (Xu, et al., 1986), and ion imaging. 

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