gamma_p = 2.6753E4; % proton
hbar = 4.136e-15; %eV*sec
k = 8.617e-5; % eV/K
E = hbar*gamma_p*1770; % Energy splitting at B_0 = 1770 gauss

alpha = E/(k*298); % room temp

relfrac = (1-exp(-alpha))/(1+exp(-alpha));