The properties of the three lowest singlet electronic states (ground, (1)L(b), and (1)L(a) states) of indole (C(8)H(7)N) have been calculated with second-order approximate coupled-cluster theory (CC2) within the resolution-of-the-identity approximation. Refined electronic energies at the CC2 optimized structures and transition dipole moments were calculated using a density functional theory multi-reference configuration-interaction (DFT/MRCI) approach. Structures, energies, and dipole moments are reported for all three states and compared to experimental values. From the optimized structures and calculated transition dipole moments, we predict that pure (1)L(b) bands will have positive signs for both the axis reorientation angle theta(T) and the angle theta of the transition dipole moment with respect to the inertial a axis. For (1)L(a) bands the signs of both angles will be reversed. Vibronically coupled bands can exhibit opposite signs for theta and theta(T). The absorption and emission spectra of indole are calculated based on the Franck-Condon Herzberg-Teller approximation using numerical transition dipole moment derivatives at the DFT/MRCI level of theory. Implications for the experimentally observed vibronic spectra are discussed. Predictions are made for rotationally resolved spectra of various rovibronic bands. A conical intersection, connecting the (1)L(b) and (1)L(a) states, which can be accessed to varying extents via different Herzberg-Teller active modes is found approximately 2000 cm(-1) above the (1)L(b) minimum.

High-resolution electronic spectra of indole (C(8)H(7)N) and their detailed analysis are reported. Thirteen low-lying vibronic bands--from the electronic origin transition at 35,231.4 cm(-1) up to 1000 cm(-1) above--are recorded with rotational resolution. Besides inertial parameters and inertial defects these spectra yield detailed information, for each individual band, on the transition-dipole-moment orientations in the molecular inertial frame as well as on the reorientation of that inertial frame upon electronic excitation. The natural lifetimes of the individual vibronic states have also been determined. Strongly varying orientations of the transition-dipole-moments, unexpected positive inertial defects, and decreasing lifetimes, which are only partly related to increased excitation energy, are observed. These results are clear indications of the interaction of the two lowest electronically excited singlet states ((1)L(b) and (1)L(a)). Our experimental findings are strongly supported by, and in excellent agreement with, the theoretical description of the interaction of the two electronic states described in the preceding paper. These results provide clear evidence for strong vibronic coupling of the two electronic states (1)L(b) and (1)L(a) and for the energetic location of the (1)L(a)-state more than 1000 cm(-1) above the (1)L(b) vibrationless state.

The structures of the van der Waals bonded complexes of phenol with one and two argon atoms have been determined using rotationally resolved electronic spectroscopy of the S(1)<--S(0) transition. The experimentally determined structural parameters were compared to the results of quantum chemical calculations that are capable of properly describing dispersive interactions in the clusters. It was found that both complexes have pi-bound configurations, with the phenol-Ar(2) complex adopting a symmetric (1mid R:1) structure. The distances of the argon atoms to the aromatic plane in the electronic ground state of the n=1 and n=2 clusters are 353 and 355 pm, respectively. Resonance-enhanced multiphoton ionization spectroscopy was used to measure intermolecular vibrational frequencies in the S(1) state and Franck-Condon simulations were performed to confirm the structure of the phenol-Ar(2) cluster. These were found to be in excellent agreement with the (1mid R:1) configuration.

Graphene has many claims to fame: it is the thinnest possible membrane, it has unique electronic and excellent mechanical properties, and it provides the perfect model structure for studying materials science at the atomic level. However, for many practical studies and applications the ordered hexagon arrangement of carbon atoms in graphene is not directly suitable. Here, we show that the atoms can be locally either removed or rearranged into a random pattern of polygons using a focused ion beam (FIB). The atomic structure of the disordered regions is confirmed with atomic-resolution scanning transmission electron microscopy images. These structural modifications can be made on macroscopic scales with a spatial resolution determined only by the size of the ion beam. With just one processing step, three types of structures can be defined within a graphene layer: chemically inert graphene, chemically active amorphous 2D carbon, and empty areas. This, along with the changes in properties, gives promise that FIB patterning of graphene will open the way for creating all-carbon heterostructures to be used in fields ranging from nanoelectronics and chemical sensing to composite materials.