TREPICO observation of the threshold region of N2O clusters

Abstract Synchrotron radiation from the electron storage ring BESSY in Berlin is used to investigate the properties of (N 2 O) n clusters in the region of the ionisation thresholds. Ionisation potentials are given and compared with a model calculation for these van der Waals' clusters. Photoionisation efficiency (PIE) spectra for small (N 2 O) n clusters with n ⩽8 were previously reported. Observation of a resonance structure slightly above the ionisation threshold for these clusters led to a discussion of the effect of exciton formation on the PIE spectra. The present Letter extends the study by presenting threshold photoelectron photoion coincidence (TREPICO) data for (N 2 O) n clusters with 2⩽ n ⩽22.