Photoelectron spectroscopy of C^-_n produced from laser ablated dehydroannulene derivatives having carbon ring size of n=12, 16, 18, 20, and 24

n-Dehydroannulenes with the ring size of n= 12, 16, 18, 20, and 24 and with three to five indanyl substituents are laser ablated by 355 nm photons. The indanyl unit is lost stepwise up to the complete deletion to leave the bare annulenyl skeleton. The monoanions of these products are mass analyzed first, and then subjected to a second laser pulse of 266 nm to obtain photoelectron spectra for C^-_n with n=12, 16, 18, 20, and 24. The spectra are compared with those obtained by using graphite as a target of the laser ablation. The comparison of the two spectra provides useful information on the structure of neutral carbon clusters.