Ulterior Considerations on the Errors in the Numerical Calculation of the Moments of ESR Absorption Curves

Abstract

In a previous paper (l), we discussed the odd momenta method for the numerical integration of the experimental ESR spectra. The method is based on the rule of integration by parts and we have shown that it may lead, for a cut Lorentzian or quasi-hrentzian line ehape, to an error up to 5 6 in the calculation of the second momenta of the absorption curves. There is an alternative method, the so-called even moments method (2), that seems to avoid such difficulties, because it is baaed on a straight double integration of the experimental derivative spectra. Actually, however, this last method leads to the same errors as the former one. In fact, for an experimental derivative curve cut at H -Ho =f a from the center, the numerical