Aasa factor

For a balanced historical record I should add that the late W. E. Blumberg has been cited to state (W. R. Dunham, personal communication) that One does not need the Aasa factor if one does not make the Aasa mistake, by which Bill meant to say that if one simulates powder spectra with proper energy matrix diagonalization (as he apparently did in the late 1960s in the Bell Telephone Laboratories in Murray Hill, New Jersey), instead of with an analytical expression from perturbation theory, then the correction factor does not apply. What this all means I hope to make clear later in the course of this book. 

The transition probability P is calculated by the perturbation formula ofBIeaney [13] corrected for the Aasa Vanngard factor [14,15]. 

The levels involved in the transition are referred to as a Kramers doublet having effective spin S = 1/2 and an effective g-factor that depends on the fs. The splitting can be obtained by measurements at two microwave frequencies, applying an analytic procedure developed by Aasa et al. several years ago [30]. Values of D for the Fe(III) ESR spectrum of lipoxygenase estimated by measurements of the effective g-values at X- and Q-band frequencies and by analysis of the temperature variation of the signal strength in the range 0.6 < D (cm ) < 3 were reported.The asymmetry... 

The first ratio is between the experimentally determined intensities, the second compensates for the difference in spin quantum numbers. The third ratio contains a correction due to differences in g-factors. For isotropic systems it has been customary to put, but as explained by Aasa and VanngSrd [3] this is not... 

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