Multi-frequency

Prabhu AV, Gogate PR, Pandit AB (2004) Optimisation of multi frequency sonochemical reactors. Chem Eng Sci 59 4991-4998... 

Feng R, Zhao Y, Zhu C, Mason TJ (2002) Enhancement of ultrasonic cavitation yield by multi-frequency sonication. Ultrason Sonochem 9 231-236... 

Analysis of the spectra at different frequencies yielded the parameters D = — 2.20(5) cm-1, = 0.0(1) cm-1, and a nearly isotropic g-factor, g = 1.98(2), none of which could have been determined at X-band. Analysis was aided by the observation of different slopes of the B vs. v plots for Ams > 1 and Ams = 1 transitions. A review of advanced methods, including high-field EPR, is given in ref. 11. Various recent applications of high field and multi-frequency EPR are described in refs 19-31. 

D. Collison, M. Helliwell, V.M. Jones, F.E. Mabbs, E.J.L. Mclnnes, P.C. Riedi, G.M. Smith, R.G. Pritchard and W.I. Cross, Single and double quantum transitions in the multi-frequency continuous wave electron paramagnetic resonance (cwEPR) of three six-co-ordinate nickel(II) complexes ... 

P.J.M. van Kan, E. van der Horst, E.J. Reijerse, P.J.M. van Bentum and W.R. Hagen, Multi-frequency EPR spectroscopy of myoglobin. Spectral effects for high-spin iron(III) at high magnetic fields, J. Chem. Soc., Faraday Trans., 1998, 94, 2975. 

Pierik, A.J., Hagen, W.R., Dunham, W.R., and Sands, R.H. 1992a. Multi-frequency EPR and high-resolution Mossbauer spectroscopy of a putative [6Fe-6S] prismane-cluster-containing protein from Desulfovibrio vulgaris (Hildenborough) characterization of a supercluster and superspin model protein. European Journal of Biochemistry 206 705-719. 

Fig. 6.6. Principles of pulse fluorometry and multi-frequency phase-modulation fluorometry.

Fig. 6.10. Schematic diagram of a multi-frequency phase-modulation fluorometer. P polarizers PC Pockel s cell S sample R reference.

Jameson D. M., Gratton E. and Hall R. D. (1984) The Measurement and Analysis of Heterogeneous Emissions by Multi-frequency Phase and Modulation Fluorometry, Appl. Spectrosc. Rev. 20, 55—... 

E. Gratton, D. M. Jameson, N. Rosato, and G. Weber, A multi-frequency cross-correlation phase fluorometer using synchrotron radiation, Rev. Sci. Instrum. 55, 486-494 (1984). 

Kamasa P, Merzlyakov M, Pyda M, Pak J, Schick C, Wunderlich B (2002) Multi-frequency heat capacities measured with different types of TMDSC. Thermochimica Acta 392-393 195-207... 

Multi-frequency EPR and High-Frequency EPR Tie, T2e (ts) geffective. Through analysis of the field/frequency dependence of electronic relaxation and geffective zero field splitting (ZFS, D, E, A2), rv. Also details of BPCA-protein interactions, including BPCA fraction bound to protein. 

The main advantage of a multi-frequency study is that it provides information on the frequency dispersion of magnetic resonance parameters. This approach (dispersion), for example, is the power in NMRD studies. Several laboratories pioneered in the application of multi-frequency EPR as a route to a more accurate evaluation of key spectroscopic parameters (g, A, Q, D, E), as well as a more sensitive methodology for studying dynamical processes, where an interplay between the frequency dependence of the spin process and the frequency dependence of the EPR observation often can provide exceptionally detailed information [64,65]. In order to take advantage of the method, the frequency dependence of spin systems must be understood. This has led to the development of several theoretical approaches for better analysis of multi-frequency data, and especially in BPCA research, for the analysis of the frequency dependence of geffective, Tle, T2e, and the overall EPR line shape in frozen glasses and in room-temperature aqueous solutions. 

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