Aspects of Physical Chemistry

Abstract

Some of those topics in physical chemistry that are especially relevant to astrochemistry and astrobiology are introduced in this chapter. I start with some discussion of the chemical elements: their relative abundances, their electronic structure, and how chemical bonds are formed in simple molecules. This leads to a discussion of how changes between energy levels lead to molecular spectra that can be used to identify molecules at a distance - even the vast distances from Earth to astronomical objects. Having considered forces within molecules, I then discuss the weaker forces between molecules, including hydrogen bonding. The next section focuses on chemical reactions from both the standpoint of thermodynamics and that of chemical kinetics. Finally, some consideration is given to surface processes, which can occur on the dust particles found in the interstellar medium, and enzyme kinetics, which is of great importance in biology.