GALLI, DanieleDanieleGALLI2024-03-012024-03-0120249780323917469http://hdl.handle.net/20.500.12386/34848This chapter contains the description of a miscellanea of microphysical processes incorporated in most numerical codes for studying the thermal and dynamical properties of the interstellar medium. They include the expressions of the ambipolar, Hall, and Ohm resistivities of a weakly ionized gas; the formulae to compute the internal energy and adiabatic index of a hydrogen-helium mixture; the relations between forward and backward cross-sections and rate coefficients according to the principle of detailed balance. The goal of this chapter is to provide a collection of ready-to-use formulae for numerical evaluation.STAMPAenBook part10.1016/B978-0-32-391746-9.00020-1https://www.sciencedirect.com/science/article/abs/pii/B9780323917469000201?via%3Dihub2024asmo.book..307GFIS/05 - ASTRONOMIA E ASTROFISICA