Reactivity under restricted geometry conditions can be quantitatively rationalized by using the Pseudophase Model. This model considers two states in equilibrium, free and bound, which are not perturbed by the reaction. That is, the reaction in which the two states participate must be slow in comparison to the exchange process between the free and bound states. This condition is fulfilled in the case of chemical reactions, but it does not hold for fast photochemical reactions. In spite of this, the Pseudo-phase Model was found to be, at least apparently, applicable for excited state reactions. However, a thorough analysis of the kinetic data brings to light important differences between the two types of reactions, particularly in the meaning of the parameters present in the equations of the Pseudophase Model.

可以使用伪相模型对在受限几何条件下的反应性进行定量合理化。该模型考虑了处于平衡状态的两个自由状态和自由状态，它们不受反应的干扰。也就是说，与自由状态和束缚状态之间的交换过程相比，这两个状态所参与的反应必须是缓慢的。在化学反应的情况下可以满足此条件，但不适用于快速的光化学反应。尽管如此，发现伪相模型至少显然适用于激发态反应。然而，对动力学数据的透彻分析揭示了两种类型反应之间的重要区别，特别是在伪相模型方程中存在的参数含义方面。