Femtosecond pump-probe experiments on non-stoichiometric sodium-fluoride clusters - I. First direct observation of periodical structural changes in Na2FC. Lupulescu, Š. Vajda, A. Lindinger, A. Merli and L. WösteEur. Phys. J. D, 24 1-3 (2003) 173-176DOI: https://doi.org/10.1140/epjd/e2003-00154-1