Physical meanings:<br>
<math>\xi</math> and <math>\eta</math> are differences of the real and imaginary components of the free precession frequencies <math>f_{00}</math> and <math>f_{11}</math> (equation (41)).<br>
<math>D_+</math> and <math>D_-</math> are the stay/stay <math>F_{0}</math>, and swap/swap <math>F_{2}</math> coefficients (equation (36)).<br>
== Parameters ==