function [dE] = splitting(n,l,j,coef)

% coef = m*c^2*(Z*alpha)^4

if (l>0)
  if (j>l)
    dE = coef./4 ./(n.^3 .* (l+1/2) .* (l+1));
  else
    dE = coef./4 ./(n.^3 .* (l+1/2) .* (-l));
  end
else
  dE = 0;
end
