Example 3: When modeling an isotropic response, the total homogeneous dephasing (T Hom ) has three contributions from pure dephasing (T 2 * ), vibrational lifetime (T LT ), and orientational relaxation (T or ) : 1/T hom = 1/T 2 * + 1/2T LT + 1/3T or . If the waiting-time axis is sufficiently well-sampled to ensure linear independence of T LT , the remaining three lifetimes T hom , T 2 * and T or are still multicollinear with one another. This is equivalent to trying to solve an algebraic equation for the values of 𝑥𝑥, 𝑦𝑦 and 𝑧𝑧 given only that 𝑥𝑥 = 𝑦𝑦 + 5/2 + 𝑧𝑧/3. There are infinite possible answers. So, we reduce the number of unknowns to simply T Hom and T LT , without specifying T 2 * and T or while fitting the isotropic response but enforce the boundary condition