where U (R) and U (R, k B T ) are a temperature-independent (T-independent) and a temperaturedependent (T-dependent) potential energy functions, respectively. U (R, k B T ) is in principle a flexible functional term as a function of both configuration R and temperature T . The separation of two terms, as seen in Equation , is expected to correspond to the mean and variance of energy distributions, or alternatively, the energetic and entropic contributions to the free energy. This choice is based on established principles and aligns with well-founded theoretical considerations. We define