Molecular formation in the stagnation region of colliding laser-produced plasmas

Laser-produced colliding plasmas have numerous attractive applications, and the stagnation layer formed during collisions between plasmas is a useful system for understanding particle collisions and molecular formation in a controlled way. In this article, we explore carbon dimer formation and its evolutionary paths in a stagnation layer formed during the interaction of two laser-produced plasmas. Colliding laser-produced plasmas are generated by splitting a laser beam into two sub-beams and then focusing them into either a single flat graphite target (laterally colliding plasmas) or a V-shaped graphite target (orthogonally colliding plasmas). C2 formation in the stagnation region of both colliding plasma schemes is investigated using optical spectroscopic means and compared with emission features from a single seed plasma. Our results show that the collisions between the plasmas followed by stagnation layer formation lead to rapid cooling, causing enhanced carbon dimer formation. In addition, plasma electron temperature, density, and C2 vibrational temperature were measured for the stagnation zone and compared with a single seed plasma.