Vibrational predissociation of aniline(water) n + (n =1–12)

Highlights: • The vibrational predissociation of PhNH₂(H₂O)_n⁺ with IR was studied. • The rate of dissociation of the clusters increases with increasing the internal energy and decreases with the size of the clusters. • The dissociation of PhNH₂(H₂O)_n⁺ ions follows the statistical theory. Vibrational predissociation dynamics of aniline(water)_n⁺ cluster ions formed via resonance two photon ionization followed by the absorption of single infrared photon was investigated. A linear tandem time of flight mass spectrometer designed for this research was tested by the dissociation of aniline⁺ at 266 nm and observed decay constant matched well with the previous result. The rate of dissociation of aniline(water)_n⁺ cluster increased with internal energy, whereas decreased with increasing the size of cluster, manifesting that the intramolecular vibrational energy redistribution precedes VP. The internal energies of the cluster ions were estimated from comparing the experimental and Rice–Ramsperger–Kassel–Marcus calculation results.