Optically detected magnetic resonance absorbance

A number of other laser spectroscopic techniques are of interest but space does not permit their discussion. A few specialized methods of detecting laser absorption worthy of mention include multiphoton ionization/mass spectrometry (28), which is extremely sensitive as well as mass selective for gas-phase systems optically detected magnetic resonance (29) laser intracavity absorption, which can be extremely sensitive and is applicable to gases or solutions (30) thermal blooming, which is also applicable to very weak absorbances in gases or liquids (31) and... 

The charged quasiparticles can be probed by electrical dc conductivity measurements (for polarons), magnetic susceptibility (for polarons and bipolarons), electron-spin resonance (ESR) (for polarons) and optical measurements (for polarons and bipolarons). As ESR is well suited for studying spin-carrying polarons, optical modification of the ESR (optically detected magnetic resonance ODMR) can be applied to link the emissive or absorbing properties of the polymer with its spin state. 

R vanderVos, PJ van Leeuwen, P Braun and AJ Hoff (1992) Analysis of the optical absorbance spectra ofD1-D2-cytochrome b559 complexes by absorbance-detected magnetic resonance. Structural properties of 6 80. Biochim Biophys Acta 1140 184-198... 

In this paper we will report results of Absorbance-Detected Magnetic Resonance (ADMR) measurements of membranes of //. chlorwn at 1.2 K. With this method the ZFS parameters are more accurately determined than with high-field EPR because of the optical selectivity of the ADMR method and the much higher resolution of this zero-field technique. Using the microwave selectivity of the ADMR method, Triplet-minus-Singlet (T-S) spectra have been obtained, under different reducing conditions, from which we have been able to ascertain the origin of the triplets of BChl g in H. chlorwn. The ZFS parameters and the decay rates of the triplet sublevels are compared with those obtained for BChl g in ethanol. 

There have been a number of important developments in light-based detection for CE since the previous edition of this work was published. For example, multichannel detection has become more common for absorbance as well as fluorescence, and Fourier transform infrared (FTIR) and nuclear magnetic resonance spectroscopies are now viable detection modes. Thus, while the purpose of this chapter is to describe the instrumentation and performance of more common optical detectors, newer methods are presented throughout. 

In addition to this quantitative information, it is also possible to obtain qualitative information about an analyte, such as the presence or absence of specific functional groups and their relative locations or orientations. A subset of the available optical detection methods are capable of providing this information, such as multiwavelength UV-Vis absorbance or fluorescence, nuclear magnetic resonance, and Raman spectroscopies these techniques will be discussed in more detail in this chapter. 

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