COMPUTER ENHANCEMENT OF CW-EPR EXPERIMENTAL SPECTRA RESOLUTION AS A NEW METHOD IN INVESTIGATION OF MOLECULAR-DYNAMICS IN PYRIDINIUM TETRAFLUOROBORATE

The present paper reports an application of the computer method for en hancing resolution of complex CW-EPR spectra. The computer resolution enhancement method (CREM) is based on the Fourier transform, convoluti on and deconvolution of functions and permits determination of the fun damental parameters of the spectra: the number of resonance lines, the ir positions, core width parameter, and relative ratios of intensities . Thanks to the use of a simulation procedure performed with the earli er determined parameters of the spectra, we were able to find the temp erature changes of the widths of individual spectral lines, An example illustrating the advantages of the CREM is the possibility of investi gation of molecular dynamics and phase transitions by the CREM-aided C W-EPR. Dynamics of the radical in a complex of pyridine with tetrafluo roboric acid is reflected in changes in the hyperfine structure, core width parameter and width of individual lines in the spectrum. These c hanges are detectable for the complex in both powdered and single-crys tal form. (C) 1998 Elsevier Science B.V. All rights reserved.