Imaging superatomic molecular orbitals in a C₆₀ molecule through four 800-nm photons

Abstract

Superatomic molecular orbitals (SAMO) in C 60 are ideal building blocks for functional nanostructures. However, imaging them spatially in the gas phase has been unsuccessful. It is found experimentally that if C 60 is excited by an 800-nm laser, the photoelectron casts an anisotropic velocity image, but the image becomes isotropic if excited at a 400-nm wavelength. This diffuse image difference has been attributed to electron thermal ionization, but more recent experiments (800 nm) reveal a clear non-diffuse image superimposed on the diffuse image, whose origin remains a mystery. Here we show that the non-diffuse anisotropic image is the precursor of the f SAMO.We predict that four 800-nm photons can directly access the 1f SAMO, and with one more photon, can image the orbital, with the photoelectron angular distribution having two maxima at 0 • and 180 • and two humps separated by 56.5 • . Since two 400-nm photons only resonantly excite the spherical 1s SAMO and four 800-nm photon excite the anisotropic 1f SAMO, our finding gives a natural explanation of the non-diffuse image difference, complementing the thermal scenario.

Superintermolecular orbitals in the C60 -pentacene complex

“…These orbitals have a distinctive shell structure from 1s up to 1d and are optically dark states. When we were investigating SAMO [15], we were keenly aware of the large size of those SAMOs. We notice that the 1s orbital has a size close to C 60 [15].…”

“…where the exchange-correlation potential V xc is δE xc [ρ]/δρ(r), taking the form of the local density approximation (LDA). We find that LDA is sufficient for our purpose, and using GGA raises the energy by 0.5 eV [15]. The new charge density is computed by summing over all the occupied orbitals (N occ ),…”

All-boron fullerene B40: a superatomic structure

“…It is particularly important that, after C 60 , B 40 is the second non-metallic cage molecule discovered by experiment. Moreover, the C 60 superatomic orbitals are contributed to the p z electrons of carbon atom [6,36], which can be used scalar harmonics [37]. Unlike C 60 , boron forms cluster bonds by both s and p orbitals, which requires the use of 40 and its ions computed at the GIAO-PBE/6-311+G* and GIAO-PBE0/6-311+G* levels of theory based on the PBE0/6-31G* structures tensor surface harmonics [38,39].…”

High-order harmonic generation in solid C60

“…The π electron cloud surrounds the carbon cage and demonstrates a high level of charge delocalization and conjugation. Beyond those normal molecular orbitals, superatomic molecular orbitals are also found [5][6][7][8][9]. Charge delocalization renders fullerite a strong and fast nonlinear optical response [10,11], with the third order susceptibility of χ (3) close to 10 −12 esu [12].…”