Experimental Evidence of Excited Multicharged Atomic Fragments Coming from Laser-Induced Coulomb Explosion of Molecules

Abstract

Direct experimental evidence is presented for the production of excited multicharged atomic fragments in the laser-induced Coulomb explosion of molecules. The comparison of the fluorescence signals of several atomic and molecular species shows that the excited fragments come from transient excited multicharged molecules. The atomic fluorescence spectra recorded with ${\mathrm{NH}}_3$, ${\mathrm{N}}_2$, and ${\mathrm{N}}_2\mathrm{O}$, in the 50–120 nm wavelength range, show that the excitation increases noticeably from ${\mathrm{NH}}_3$ to ${\mathrm{N}}_2\mathrm{O}$. This effect is interpreted in terms of the initial electronic configuration, which favors a stronger excitation when the electronic density is more delocalized on the molecular nuclear structure.