Valence shell electron pair repulsion (VSEPR<span>) </span>theory<span> is a model used in chemistry to predict the geometry of individual molecules from the number of electron pairs surrounding their central atoms. It is also named the Gillespie-Nyholm </span>theory<span> after its two main developers.
</span>The London theory has much similarity to the quantum mechanical theory of light dispersion<span>, which is why London coined the phrase "dispersion effect." In physics, the term "dispersion" describes the variation of a quantity with frequency, which is the fluctuation of the electrons in the case of the London dispersion.</span>
