ABSTRACT
This chapter presents a brief account on both approaches, analytic and synthetic, within chemistry. It reviews the different levels at which molecular systems are traditionally studied. The chapter explores the Born–Oppenheimer approximation and then revisiting the methodologies available to deal with both electronic configuration and dynamics, distinguishing in this latter case between molecular dynamics for a few degree-of-freedom systems and statistical mechanics. It focuses on some fundamental aspects of Bohmian mechanics and describes some specific illustrations of the application of Bohmian mechanics to problems typical of the levels mentioned. Molecular systems typically include a rather large number of degrees of freedom, which makes unaffordable their direct study. In the wave model each atom is assumed to be a point-like, positively charged nucleus surrounded by an electronic cloud, which is associated with a certain orbital and represents the electron probability distribution in configuration space.
