The model-free Hessian of the original spectral density function (15.62) is the matrix of second partial derivatives. The matrix coordinates correspond to the model parameters which are being optimised.
The second partial derivative of (15.62) with respect to the geometric parameters and is
The second partial derivative of (15.62) with respect to the geometric parameter and the orientational parameter is
The second partial derivative of (15.62) with respect to the geometric parameter and the order parameter S^{2} is
The second partial derivative of (15.62) with respect to the geometric parameter and the correlation time τ_{e} is
The second partial derivative of (15.62) with respect to the orientational parameters and is
= τ_{i} + . | (15.66) |
The second partial derivative of (15.62) with respect to the orientational parameter and the order parameter S^{2} is
= τ_{i} - . | (15.67) |
The second partial derivative of (15.62) with respect to the orientational parameter and the correlation time τ_{e} is
= (1 - S^{2})τ_{i}^{2}. | (15.68) |
The second partial derivative of (15.62) with respect to the order parameter S^{2} twice is
= 0. | (15.69) |
The second partial derivative of (15.62) with respect to the order parameter S^{2} and correlation time τ_{e} is
= - c_{i}τ_{i}^{2}. | (15.70) |
The second partial derivative of (15.62) with respect to the correlation time τ_{e} twice is
= - (1 - S^{2})c_{i}τ_{i}^{2} | (15.71) |
The relax user manual (PDF), created 2020-08-26.