Physical chemistry is the study of macroscopic, atomic, subatomic, and particulate phenomena in chemical systems in terms of laws and concepts of physics. * Chemical kinetics, also known as reaction kinetics, is the study of rates of chemical processes. Chemical kinetics includes investigations of how different experimental conditions can influence the speed of a chemical reaction and yield information about thereaction's mechanism and transition states, as well as the construction of mathematical models that can describe the characteristics of a chemical reaction. * Chemical physics is a subdiscipline of chemistry and physics that investigates physicochemical phenomena using techniques from atomic and molecular physics and condensed matter physics; it is the branch of physics that studies chemical processes from the point of view of physics. * Electrochemistry is a branch of chemistry that studies chemical reactions which take place in a solution at the interface of an electron conductor (theelectrode: a metal or a semiconductor) and an ionic conductor (the electrolyte). * Femtochemistry is the area of physical chemistry that studies chemical reactions on extremely short timescales, approximately 10–15 seconds (one femtosecond, hence the name). The steps in some reactions occur in the femtosecond timescale and sometimes in attosecond timescales,[1] and will sometimes form intermediate products. * Geochemistry is the science that uses the tools and principles of chemistry to explain the mechanisms behind major geological systems such as the Earth's crust and its oceans.[1] The realm of geochemistry extends beyond the Earth, encompassing the entire Solar System * Photochemistry, a sub-discipline of chemistry, is the study of chemical reactions that proceed with the absorption of light by atoms or molecules. * Quantum chemistry is a branch