A general formalism to describe the stereodynamics of bond axis orientation in the scattering of a linear molecule with an atom

One of the aims of the chemist is to obtain the greatest possible level of control over the outcome of a reaction. A factor that can influence such outcomes is the so-called steric effect. The underpinning idea of this effect is that the mutual orientation of the collision partners at the moment of collision may impact the nature of the products. The steric effect has been studied in a variety of ways, notably using optical methods, as well as making use of both magnetic and electric fields, to orient or align reactants. Here, we present a general framework for interpreting and evaluating steric effects in collisions of open shell linear molecules with an atom in the presence of an electric field. While in previous studies, the theory has been limited to the specific system of interest, such as for the end-on collisions of NO(X), this new formalism provides a fundamental basis for examining any system of this type. Some examples of the utility and power of this formalism are also provided. This theory may then be built on further in the future to provide greater insights into the stereodynamics of collisions and, hence, provide the foundation for deeper study into how the steric effect may be harnessed for control.