Higher resolution photoionization study of acetylene near the threshold

Abstract
High resolution (0.14 Å FWHM) photoionization efficiency data for C2H2+ near the threshold (1059–1090 Å) have been obtained using the molecular beam method. The positions of the autoionization features resolved on the v2=0 vibrational step of C2H2+(X̃ 2Πu) were found to be consistent with those calculated from the two Rydberg equations νn=93 770−[R/(n−0.95)2] cm−1, νn=93 770−[R/(n−0.36)2] cm−1, where R and n are the Rydberg constant and the principal quantum number, respectively.