Mode specific photodissociation of CS2+via the A2Πu state: a time-sliced velocity map imaging study

Abstract

The vibrationally mediated photodissociation of CS₂⁺ cations via the A²Π_u(ν₁,ν₂,0) state has been studied by means of the velocity map ion imaging technique. The measurements were made with a double resonance strategy. The CS₂⁺ cations were prepared by a (3 + 1) resonance enhanced multiphoton ionization method. The photo-fragment excitation spectrum of S⁺ was recorded by scanning the photolysis laser via the A²Π_u(ν₁,ν₂,0) state. By fixing the photolysis laser wavelength at the specific vibrational state, the (1 + 1) photodissociation images of S⁺ photofragments from numerous vibrationally mediated states have been accumulated. The translational energy release spectra derived from the resulting images imply that the co-fragments, CS radicals, are both vibrationally and rotationally excited. The one-photon photodissociation without the vibrational state selection has also been performed. Comparing the vibrationally mediated photodissociation with one-photon photodissociation observations, clear evidence of vibrational state control of the photodissociation process is observed.