Single ≤1 kJ pulses from a high-power laser are focused into molecular gases to create large laser sparks [1-5]. This provides a unique way to mimic the chemical effects of high-energy-density events in planetary atmospheres (cometary impact, lightning) matching the natural energy-density and plasma-volume scaling of such events in a fully-controlled laboratory environment. The many chemical reactions initiated by laser-induced dielectric breakdown (LIBD) in both neat molecular gases and in mixtures with compositions related to the study of the chemical evolution of the Earth’s early atmosphere are systematically studied. The processes [2,4] responsible for the chemical action of laser sparks are identified and investigated. The results of our high-energy single-pulse experiments are compared with results obtained with many low-energy pulses from high-repetition-rate lasers, where reaction products from earlier pulses may undergo additional reactions due to LIDB by later pulses.
References:
1. S. Civiš, L. Juha, D. Babánková, J. Cvačka, O. Frank, J. Jehlička, B. Králiková, J. Krása, P. Kubát, A. Muck, M. Pfeifer, J. Skála, J. Ullschmied: Amino acid formation induced by a high-power laser in CO
2/CO-N
2-H
2O gas mixtures, Chem. Phys. Lett.
386, 169 (2004).
2. D. Babánková, S. Civiš, L. Juha: Chemical consequences of laser-induced breakdown in molecular gases, Prog. Quant. Electron.
30, 75 (2006).
3. S. Civiš, D. Babánková, J. Cihelka, P. Sazama, L. Juha: Spectroscopic investigations of high-power laser-induced dielectric breakdown in gas mixtures containing carbon monoxide, J. Phys. Chem. A
112, 7162 (2008).
4. L. Juha, S. Civiš: Laser-plasma chemistry: Chemical reactions initiated by laser-produced plasmas, In: Lasers in Chemistry (Ed. M. Lackner), Vol. 2, Wiley-VCH, Weinheim 2008, pp. 899-921.
5. M. Ferus, I. Matulková, L. Juha, S. Civiš: Investigation of laser-plasma chemistry in CO-N
2-H
2O mixtures using
18O labeled water, Chem. Phys. Lett.
472, 14 (2009).
