Reassessing the orbitals of pi systems using photoinduced Ryberg ionization spectroscopy

Photoinduced Rydberg Ionization Spectroscopy of Phenylacetylene: Vibrational Assignments of the C̃ State of the Cation

“…In benzene and phenol, the energy of the 2 B 2 σ state is below that of 2 B 1 , whereas in fluorobenzene and chlorobenzene that ordering is reversed because of the interaction of the halogen out-of-plane 2p orbital with the ring. 1 In phenylacetylene, there is a more extensive π system on the acetylene group, and it is of interest to confirm the σ-π ordering in this molecule.…”

“…These two states are formed from the removal of an electron from either the highest 2p σ orbital or from one of the two orbitals formed from the interaction of the lowest ring π orbital with a 2p or π orbital on the substituent. 1 The former symmetry (in C 2V ) is 2 B 2 , and the latter is 2 B 1 . In benzene and phenol, the energy of the 2 B 2 σ state is below that of 2 B 1 , whereas in fluorobenzene and chlorobenzene that ordering is reversed because of the interaction of the halogen out-of-plane 2p orbital with the ring.…”

Multireference Configuration Interaction Study of the Vibronic Transitions and Photodissociation of Vinyl Bromide and Vinyl Chloride Radical Cations in the Second Excited State

“…13,14 This method has been successfully applied for observation of forbidden X ˜-B ˜transitions in benzene and halobenzenes. [15][16][17][18] Kim et al found that radical cations of vinyl halides generated by chemical exchange or electron impact are fairly long-lived, 19 and they measured the kinetic energy released and angular distribution of the C 2 H 3 + fragment from C 2 H 3 Cl + at several excitation wavelengths. 20 Recently, they developed a new technique called MATI photofragment yield (PFY) spectroscopy by scanning the excitation energy and detecting dissociated ions after photoexcitation of radical cations generated by the MATI method.…”

Mass-Analyzed Threshold Ionization Spectra of C6H6+ and C6D6+ Obtained via the 3B1u Triplet State

“…The reader desiring a more in-depth understanding of the JT effect is referred to one of the many review articles written on the subject, 24,25 or two recent papers focused exclusively on the JT effect in the benzene cation. 26,27 It has been evident in several previous studies [28][29][30][31] of benzene and substituted benzene cations, using photoinduced Rydberg ionization (PIRI) spectroscopy, [31][32][33] that it is rarely possible to unambiguously understand the vibrational structure of a state using only a spectrum from a single lower state. There is not enough information in a single spectrum to resolve the multitude of possible assignments available in the dense vibrational manifolds of these states.…”

“…It has been evident in several previous studies − of benzene and substituted benzene cations, using photoinduced Rydberg ionization (PIRI) spectroscopy, − that it is rarely possible to unambiguously understand the vibrational structure of a state using only a spectrum from a single lower state. There is not enough information in a single spectrum to resolve the multitude of possible assignments available in the dense vibrational manifolds of these states.…”