Electric resonance

Figure Cl.3.1. Schematic diagram of a molecular beam electric resonance spectrometer. (Taken from [60].)...

In dimers composed of equal molecules the dimer components can replace each other through tunneling. This effect has been discovered by Dyke et al. [1972] as interconversion splitting of rotational levels of (HF)2 in molecular beam electric resonance spectra. This dimer has been studied in many papers by microwave and far infrared tunable difference-frequency laser spectroscopy (see review papers by Truhlar [1990] and by Quack and Suhm [1991]). The dimer consists of two inequivalent HE molecules, the H atom of one of them participating in the hydrogen bond between the fluorine atoms (fig. 60). PES is a function of six variables indicated in this figure. 

Dyke, T.R., Mack, K.M. and Muenter, J.S. (1977) The structure of water dimer from molecular beam electric resonance spectroscopy, J. Chem. Phys., 66,498-510. 

Similarities with classical waves are considered. In particular we propose that the networks of electric resonance RLC circuits may be used to study wave chaos. However, being different from quantum billiards there is a resistance from the inductors which gives rise to heat power and decoherence. 

Anderson, A. G., and Hartmann, S. R., Magnetic and Electric Resonance and Relaxation, Ed. J. Smidt, North-Holland Publishing Company, Amsterdam, 1963. 

In applications where high power density or thermal management is of prime importance, hard- switched converters are not feasible using conventional Si components. In these cases, resonant or quasi-resonant (also termed soft-switching ) topologies can be used. The electrical resonance is obtained through parasitic... 

Other measurements. Induced dipole moments can be measured by most of the familiar methods that are designed to measure permanent dipole moments. We mention in particular the beam deflection method by electric fields, using van der Waals molecules, and molecular beam electric resonance spectroscopy of van der Waals molecules [373, 193, 98]. 

While the fine structure transitions are inherently magnetic dipole transitions, it is in fact easier to take advantage of the large A = 1 electric dipole matrix elements and drive the transitions by the electric resonance technique, commonly used to study transitions in polar molecules.37 In the presence of a small static field of 1 V/cm in the z direction the Na ndy fine structure states acquire a small amount of nf character, and it is possible to drive electric dipole transitions between them at a Rabi frequency of 1 MHz with an additional rf field of 1 V/cm. 

A good example of the use of the electric resonance technique is the measurement of the Na nd fine structure intervals and tensor polarizabilities.38 These transitions were observed using selective field ionization, although they appear to be unlikely prospects for field ionization detection because of the small separations of the levels, 20 MHz. The nd3/2 states were selectively excited from the 3p1/2 state in a small static electric field and the = 0 transitions to the nd5/2 states induced by a... 

The structure of the water dimer found by Dyke et al. [1977] from microwave electric resonance spectra of a supersonic molecular beam is... 

Hydroxide molecular anions (OH-) adopt [100] off-center states in alkali chlorides and bromides. These centers have six equivalent positions with different alignments of the dipoles. Electric resonance measurements give the tunneling splitting values 1.95 and 0.17 cm-1 for NaChOH- and KC1 OH-, respectively. 

Vibrational product state distributions have been obtained for reactions studied in crossed molecular beams using the technique of beam electric resonance spectroscopy [109]. This method uses the focusing action of electric quadrupole and dipole fields to measure the radio frequency Stark spectrum of the reaction products, which must possess a dipole moment. This has restricted this technique to reactions producing alkali halides. 

Electric resonance analysis [312] of the CsF product from Cs + SF4 indicates that the vibrational distribution consists of two superimposed Boltzmann distributions with very different temperatures ( 410 and 2740 K). This is in contrast to the single vibrational temperature found for Cs + SF6 and is thought to arise from the reaction with the two different types of S—F bond in SF4. Reaction with the polar bond is more highly favoured, constituting > 95% of the total reaction, and gives the higher temperature component. 

The interpretation of the microwave spectra recorded in the molecular beam electric resonance experiments shows that the dipole moment increases on complex... 

Fig. 2. J = 1, Mj = 0- 1 molecular beam electric resonance for (H20)2 at an electric field strength of 599.50V/cm. The triplet nuclear spin state gives rise to the four spin-spin components of this transition. (Reproduced from Ref.

The linewidths are quite small, roughly 10 kHz, and are caused by a Doppler dephasing as the molecules with a given polarization phase move into a region of space where they would have a different phase. There is in addition a splitting of each line ( 25 kHz) caused by Doppler effects. Nonetheless the resolution is nearly as good as in the electric resonance experiments, allowing precision rotational constants and nuclear hyperfine interactions to be measured. 

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