Excitation of Rydberg Series inC60

Abstract

Rydberg series of C60 are reported for the first time. The Rydberg states are seen in photoelectron spectra using ultrashort pulsed-laser excitation, where the excited states formed are ionized with one further photon from the same laser pulse. The structure is observed for pulse durations as short as 100 fs with indications of residual structure for even shorter pulse excitation. The production mechanism is discussed and the Rydberg states are modeled by analytically solving the Schrödinger equation with a simple jelliumlike potential for C60.

Coherent Electronic Wave Packet Motion inC60Controlled by the Waveform and Polarization of Few-Cycle Laser Fields

“…Angularly resolved photoionization by ultrashort laser pulses has been advocated for probing the electronic dynamics before the onset of significant nuclear motion (see, e.g., [27][28][29][30][31] [36,37], and efficient high-harmonic generation [38][39][40]. The ionization and fragmentation of C 60 have been investigated extensively in the past (see, e.g., [35,[41][42][43][44][45][46][47]). C 60 is very stable and is one of the few molecular systems for which the ionization energy is smaller than the lowest fragmentation threshold.…”

Super-atom molecular orbital excited states of fullerenes

“…The same group also showed the formation of nearly free electron bands when fullerenes aggregated to form a two-dimensional crystal on the metal surface, indicating that these could be interesting systems for molecular electronics applications if the excitation energy of the SAMOs could be tuned to be closer to the Fermi energy. The excited SAMOs were observed earlier in gas-phase C 60 by femtosecond photoelectron spectroscopy; however, they were not specifically identified as such [5], and they have also been observed in two-photon photoemission experiments on C 60 layers deposited on surfaces [6].…”

“…The details of the experimental techniques have been provided in previous publications [5,8,9] and will be only briefly described here. The original studies that reported the excitation and subsequent single-photon ionization of Rydberg states in C 60 were carried out with a combined linear time-of-flight photoelectron spectrometer and a time-of-flight mass spectrometer (MS) [5,10].…”

“…There have been a number of attempts to model C 60 and X@C 60 photoionization using simple, spherically symmetric, phenomenological potentials [5,7,[31][32][33]. Usually in these studies, the depth, width and shape of the potential well are adjusted to fit the experimental results and has often taken the form of a quasi-square well potential at the position of the carbon atoms.…”

“…Excitation and ionization with 800 nm, 1.5 ps bandwidth limited picosecond laser pulses produced photoelectron spectra where the higher-lying states were well resolved [5]. The assignment of the peaks was made by comparing the experimental binding energies with the numerical solution of the Schrödinger equation using a simple model potential [5].…”