Comparison of the dissociative ionization of CS₂ in intense laser fields and by charged particle impact: orientational effects caused by light polarization?

Abstract

A comprehensive comparative study of dissociative ionization of a linear triatomic species, carbon disulphide (S-C-S), has been made using a battery of different interactions involving (i) intense laser fields, (ii) fast, highly-charged, positive ion projectiles (90 MeV Si⁸⁺ and F⁷⁺), (iii) negative ion projectiles (70 keV O^-, Si^- and C^-) and (iv) fast (700 eV) electrons. The main focus is on the fragmentation channel which gives rise to the formation of S₂⁺ dimer ions from CS₂. It is found that while S₂⁺ dimers are formed in all the collisional interactions involving charged projectiles, dissociative ionization of CS₂ by intense (10¹²-10¹⁴ W cm^-2) 532 nm and 1064 nm laser fields does not proceed along the S₂⁺+C dissociation channel. Differences in the interactions which lead to dissociative ionization of CS₂ are discussed, particularly with reference the interaction with intense laser fields in which the linear CS₂ molecule tends to have its S-C-S axes strongly aligned in the direction of the polarization vector.