*2.3.4 Laser irradiation*

A current technique for co-crystallization described by Titapiwatanakun et al. uses carbon dioxide irradiation treatment for the production of a malonic acid:caffeine (1:2) and oxalic acid:caffeine (1:2) co-crystals. The energy given to the unit throughout irradiation spawns a quick escalation in heat in a short period, triggering the softening of the crystalline compound, monitored by material intermixing, and next prompts recrystallization upon freezing. In this scheme, requirements for a co-crystal former component that can be used for this process are that a co-crystal former is necessarily sublimable, to accelerate a cloud seeding method by the vapor phase [35].
