Sodium doping and reactivity in pure and mixed ice nanoparticles Jozef Lengyel, Andriy Pysanenko, Peter Rubovič and Michal Fárník Eur. Phys. J. D, 69 12 (2015) 269 Published online: 08 December 2015 DOI: 10.1140/epjd/e2015-60532-6