Since form I is a stable polymorph of TPA between 70 and 300 K, the temperature range of interest in this study, we have restricted our calculations to form I. The crystal structure of this form was taken from the Cambridge Crystallographic Data Centre under the de-position number 1269122 and is optimized using the Broyden-Fletcher-Goldfarb-Shanno 56 (BFGS) algorithm where the electronic structure was calculated using the Quickstep 57 module, which is a Gaussian and Plane wave (GPW) based implementation of Density Functional Theory, in the open source CP2K 58 package. The electronic exchange and correlation are approximated within the generalized gradient approximation (GGA) framework proposed by Becke-Lee-Yang-Parr 59,60 (BLYP). van der Waals interactions have been included using the Grimme's D3 dispersion correction. The electron-ion interactions were described by the norm-conserving, separable, dual-space Gaussian-type pseudopotentials of Goedecker, Teter, and Hutter 62 (GTH). The triple-zeta valence polarisation (TZVP) basis set was used to expand the electronic wavefunctions. The charge density was expanded on a grid with a plane wave cutoff of 450 Ry. The electronic calculations were done using a 2×2×5 supercell.