Resonant continuous electric field

We assume that the molecule-field coupling is dominated by the dipole transition interaction and represents the resonant continuous electric field e(f) in the form... 

Equation (2.19) is a complicated function of time t, frequency u , and transition frequency Wfi. Shortly after the perturbation is switched on, all molecular states become populated. However, as the electric field continues to drive the molecule with constant frequency u only the resonant transition with Ufi u> prevails while the probabilities for the nonreso-nant transitions remain negligibly small. The excitation of an atom or molecule by the electric field is formally equivalent to the excitation of an oscillator by an external periodic perturbation with constant frequency. Using the representation... 

CW = continuous-wave CW-NQR = continuous wave NQR DFT = density fiuictional theory EFG = electric field gradient IR = infrared NMR = nuclear magnetic resonance NQR = nuclear quadmpole resonance OSSE = octahedral site stabilization energy PAC = perturbed angular correlation pulse-FT = pulse-fourier transform TMED = tetramethylethylenediamine. 

Molecular motion in the polar organic solvent nitrobenzene, induced by both continuous and pulsed electronic fields, was studied by magnetic resonance imaging. The resultant image correlation spectra indicate that the time scale of motion in a 9.6 kV cm electric field is tens of milliseconds. The data were analyzed by the Fokker-Planck probability function for one-dimensional bounded diffusion. 

The sample inlet is constituted of a heated fused silica capillary, which is maintained at approximately 200 "C and is encased in a flexible tube. The ion source, in the case of electronic ionization, is composed of electrically heated metallic filaments. Mass analyzers, separating the analytes, include time-of-flight (TOF), linear quadmpole (Q), linear quadrupole ion trap (LIT), quadmpole ion trap (QIT), Fourier transform ion cyclotron resonance (FT-ICR), etc. These detectors differ in their capacity to treat ion beams in a continuous or pulsed (TOF). Quadmpole mass analyzers stabilize and destabilize the ion paths with an oscillating electrical field. A triple quad is more recent technology and consists of three quadmpole stages. Quadmpole ion traps will sequentially eject ions that have been trapped in a ring electrode between two endcap electrodes. 

ABSTRACT A brief history of the behavior of materials in nonuniform electrical fields is presented, followed by a theory of dielectrophoretic force and the derivation of the general force equation. Attention is paid to the several classes of polarization which lead to the experimental considerations of induced cellular dielectrophoresis. A distinction between batch and continuous methods is discussed, with a focus on a new microtechnique. While dielectrophoresis can induce aggregation of materials, i.e., cells, other orientational applications exist. Cell division, cellular spin resonance, and pulse-fusion of cells form topics appropriate to the realm of high-frequency electrical oscillations and are discussed in the context of living material. 

Once ions enter the analyzer region B in Figs. 1 and 4), they are affected by two independent electric fields (i.e., an rf electric field and a dc electric field). As described in Eq. (12), the radius of the trajectory of an ion which is not in resonance in the analyzer is bounded, and the ion will continue to drift in the x direction. Since the analyzer drift potential can be varied independently of the source drift potential, the drift velocity may be faster or slower in that region. The essential feature is simply that a flow of ions down the long axis of the cell can be maintained without focusing or appreciably accelerating the ions. 

After a short time delay the fragment of interest is state-selectively ionized. For this, usually a second laser is used whose photon energy is tuned to a suitable resonance transition for REMPI. The expansion of the now ion spheres continues as before, since any excess kinetic energy is basically carried away by the photoelectron. However, the ion trajectories are affected when an electric field is applied, which is poled and tailored (ion optics) in such a way to accelerate the ions towards the field-free TOF tube. 

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