Neutral C60 Research Articles

Transition probabilities and radiative lifetimes of C[formula omitted]: A high level theoretical investigation

Dicarbon species are of particular interest within the physical chemistry community. However, contrary to neutral C2, the theory of electronic structure and spectra concerning C2− ions is not well-established. To address this gap in information, high-level multireference configuration interaction (MRCI) calculations have been performed, and new potential energy curves for fourteen low-lying states of C2− are reported. The best estimate for the ground dissociation energy is 64,720 cm−1 at the MRCI+Q/AV5Z level of theory. The first excited state, A2Πu, lies at 3,836 cm−1 (Re = 2.4829 a0 and ωe = 1649 cm−1). The infrared A2Πu − X2Σg+ transition has Einstein coefficients of the order of 103–104 s−1. The lifetime of the A2Πu state is given in microseconds. For the B2Σu+ state, it was calculated τ0≈ 78 ns in good accord with the experimental value of 77 ± 8 ns. The a4Σu+ state is placed at an excitation energy of 32,369 cm−1, much higher than expected by experimentalists (19,448 cm−1). The spin-forbidden transitions a4Σu+ − X2Σg+ are strong enough to be detected experimentally (A04≈ 3 × 106 s−1). The 14Πg − a4Σu+ transitions are more concentrated in the IR region. The radiative lifetime of 14Πg is computed to be 12μs. There is no doubt that the current data considerably enhance our understanding of the spectroscopy of C2−.

Realization of Organocerium-Based Fullerene Molecular Materials Showing Mott Insulator-Type Behavior.

Electron-rich organocerium complexes (C5Me4H)3Ce and [(C5Me5)2Ce(ortho-oxa)], with redox potentials E1/2 = -0.82 V and E1/2 = -0.86 V versus Fc/Fc+, respectively, were reacted with fullerene (C60) in different stoichiometries to obtain molecular materials. Structurally characterized cocrystals: [(C5Me4H)3Ce]2·C60 (1) and [(C5Me5)2Ce(ortho-oxa)]3·C60 (2) of C60 with cerium-based, molecular rare earth precursors are reported for the first time. The extent of charge transfer in 1 and 2 was evaluated using a series of physical measurements: FT-IR, Raman, solid-state UV-vis-NIR spectroscopy, X-ray absorption near-edge structure (XANES) spectroscopy, and magnetic susceptibility measurements. The physical measurements indicate that 1 and 2 comprise the cerium(III) oxidation state, with formally neutral C60 as a cocrystal in both cases. Pressure-dependent periodic density functional theory calculations were performed to study the electronic structure of 1. Inclusion of a Hubbard-U parameter removes Ce f states from the Fermi level, opens up a band gap, and stabilizes FM/AFM magnetic solutions that are isoenergetic because of the large distances between the Ce(III) cations. The electronic structure of this strongly correlated Mott insulator-type system is reminiscent of the well-studied Ce2O3.

Photoinduced Electron Transfer in Inclusion Complexes of Carbon Nanohoops.

ConspectusPhotoinduced electron transfer (PET) in carbon materials is a process of great importance in light energy conversion. Carbon materials, such as fullerenes, graphene flakes, carbon nanotubes, and cycloparaphenylenes (CPPs), have unusual electronic properties that make them interesting objects for PET research. These materials can be used as electron-hole transport layers, electrode materials, or passivation additives in photovoltaic devices. Moreover, their appropriate combination opens up new possibilities for constructing photoactive supramolecular systems with efficient charge transfer between the donor and acceptor parts. CPPs build a class of molecules consisting of para-linked phenylene rings. CPPs and their numerous derivatives are appealing building blocks in supramolecular chemistry, acting as suitable concave receptors with strong host-guest interactions for the convex surfaces of fullerenes. Efficient PET in donor-acceptor systems can be observed when charge separation occurs faster than charge recombination. This Account focuses on selected inclusion complexes of carbon nanohoops studied by our group. We modeled charge separation and charge recombination in both previously synthesized and computationally designed complexes to identify how various modifications of host and guest molecules affect the PET efficiency in these systems. A consistent computational protocol we used includes a time-dependent density-functional theory (TD-DFT) formalism with the Tamm-Dancoff approximation (TDA) and CAM-B3LYP functional to carry out excited state calculations and the nonadiabatic electron transfer theory to estimate electron-transfer rates. We show how the photophysical properties of carbon nanohoops can be modified by incorporating additional π-conjugated fragments and antiaromatic units, multiple fluorine substitutions, and extending the overall π-electron system. Incorporating π-conjugated groups or linkers is accompanied by the appearance of new charge transfer states. Perfluorination of the nanohoops radically changes their role in charge separation from an electron donor to an electron acceptor. Vacancy defects in π-extended nanohoops are shown to hinder PET between host and guest molecules, while large fully conjugated π-systems improve the electron-donor properties of nanohoops. We also highlight the role of antiaromatic structural units in tuning the electronic properties of nanohoops. Depending on the aromaticity degree of monomeric units in nanohoops, the direction of electron transfer in their complexes with C60 fullerene can be altered. Nanohoops with aromatic units usually act as electron donors, while those with antiaromatic monomers serve as electron acceptors. Finally, we discuss why charged fullerenes are better electron acceptors than neutral C60 and how the charge location allows for the design of more efficient donor-acceptor systems with an unusual hypsochromic shift of the charge transfer band in polar solvents.

EVALUATION OF THE POTENTIAL NEUROACTIVITY IN THE BRAIN NERVE TERMINALS OF THE C60 FULLERENE PLANETARY DUST COMPONENT

A study of the infrared spectrum of the environment of the planetary nebula Tc 1 revealed the radiation of cold and neutral fullerenes C60 and C70. The results of the analysis of infrared spectra obtained using the Hubble space telescope conclusively proved the existence of C60+ fullerene in the interstellar medium. These large carbon-containing molecules can form and exist in the interstellar medium and are candidates to explain many diffuse interstellar absorption bands. In this study, the potential neuroactivity of the C60 fullerene as a planetary dust component was assessed in the isolated rat brain nerve terminals. It was shown that C60 fullerene in the unirradiated state at concentrations of 0.05—0.25 mg/ml did not change the extracellular levels of excitatory neurotransmitter L-[ 14C]glutamate and inhibitory neurotransmitter [ 3H]GABA in the preparations of rat brain nerve terminals. An increase in fullerene C60 concentrations up to 0.5 and 1.00 mg/ml was accompanied by an increase in the extracellular levels of L-[ 14C]glutamate and [3 H]GABA in the preparations of nerve terminals. Therefore, fullerene C60 did not cause signs of acute neurotoxicity in the brain nerve terminals within the concentration range of 0.05—0.25 mg/ml. However, given that C60 undergoes photooxidation, it can be expected that it may acquire neurotoxic properties in situ.

Reconsidering the Structures of C2 Al4 - and C2 Al5.

The study of C2 Al4 -/0 and C2 Al5 -/0 was conducted using anion photoelectron spectroscopy and quantum chemical computations. The present findings reveal that C2 Al4 - has a boat-like structure, with a single C2 unit surrounded by four aluminum atoms. In contrast, the neutral C2 Al4 species adopts a D2h planar structure with two planar tetracoordinate carbon (ptC) units, consistent with previous reports. Furthermore, the global minimum isomer of C2 Al5 - adopts a D3h symmetry, where the C2 unit interacts with five aluminum atoms. It was also found that a lower symmetry structure of C2 Al5 - , where all five aluminum atoms are located on the same side of the C2 unit, albeit slightly higher in energy compared to the D3h structure. These computations show that the D3h structure of C2 Al5 - is highly stable, exhibiting a large HOMO-LUMO gap.

Buckyball-metal Complexes as Potential Carriers of Astronomical Unidentified Infrared Emission Bands

Efforts over 40 yr still leave the source of astronomical infrared emission bands largely unidentified. Here, we report the first laboratory infrared (6–25 μm) spectra of gas-phase fullerene-metal complexes, [C60-Metal]+ (Metal = Fe, V) and show with density functional theory calculations that complexes of C60 with cosmically abundant metals, including Li, Na, K, Mg, Ca, Al, V, and Fe, all have similar spectral patterns. Comparison with observational infrared spectra from several fullerene-rich planetary nebulae demonstrates a strong positive linear cross-correlation. The infrared features of [C60-Metal]+ coincide with four bands attributed earlier to neutral C60 bands and in addition also with several bands unexplained to date. Abundance and collision theory estimates indicate that [C60-Metal]+ could plausibly form and survive in astrophysical environments. Hence, [C60-Metal]+ are proposed as promising carriers, in supplement to C60, of observational bands, potentially representing the largest molecular species in space other than C60, C60 +, and C70.

On the Presence of Metallofullerenes in Fullerene-rich Circumstellar Envelopes

The presence of neutral C60 fullerenes in circumstellar environments has been firmly established by astronomical observations as well as laboratory experiments and quantum-chemistry calculations. However, the large variations observed in the C60 17.4 μm/18.9 μm band ratios indicate that either additional emitters should contribute to the astronomical infrared (IR) spectra or unknown physical processes exist besides thermal and UV excitation. Fullerene-based molecules such as metallofullerenes and fullerene-adducts are natural candidate species as potential additional emitters, but no specific specie has been identified to date. Here we report a model based on quantum-chemistry calculations and IR spectra simulation of neutral and charged endo(exo)hedral metallofullerenes, showing that they have a significant contribution to the four strongest IR bands commonly attributed to neutral C60. These simulations may explain the large range of 17.4 μm/18.9 μm band ratios observed in very different fullerene-rich circumstellar environments like those around planetary nebulae and chemically peculiar R Coronae Borealis stars. Our proposed model also reveals that the 17.4 μm/18.9 μm band ratio in the metallofullerenes simulated IR spectra mainly depends on the metal abundances, ionization level, and endo/exoconcentration in the circumstellar envelopes. We conclude that metallofullerenes are potential emitters contributing to the observed IR spectra in fullerene-rich circumstellar envelopes. Our simulated IR spectra indicate also that the James Webb Space Telescope has the potential to confirm or refute the presence of metallofullerenes (or even other fullerene-based species) in circumstellar environments.

Spectroscopy of He atom encapsulated in C60 cage: low lying magnetic dipolar (M1) and magnetic quadrupolar (M2) transitions

The spectroscopic properties of magnetic dipolar and quadrupolar transitions (M1 and M2) of He atom encapsulated under neutral and charged C60 fullerene cage have been estimated here to understand the effect of cage confinement on the ground state energy ( E), ionization potential (IP), excitation energies (Δ E), and transition probabilities (TPs) of the low lying transitions 1s2:1Se → 1s ns:3S[Formula: see text] and 1s2:1Se → 1s np:3P[Formula: see text] ( n = 2, 3, 4, 5). The methodology adopted is the time-dependent coupled Hartree–Fock theory within a variational scheme, which incorporates partial correlation effects. The effect of encapsulation has been introduced through an effective potential in the one particle potential part due to the fullerene cage. Interesting pattern of the relevant properties of the confined He atom has been observed depending upon overall charge of the fullerene cage.

Revival of resonance shape parameter in elastic scattering of H atom with charged fullerenes C60z+

Abstract Scattering resonances in the elastic collision of a hydrogen atom with positively charged fullerenes (C60z+) are studied computationally employing different model potentials. Interaction potentials of H atom with charged fullerenes are simulated by varying heights of the barrier maxima offered by the fullerene C60 species. Scattering cross-section of different partial waves exhibit resonances in the background of glory oscillations. Though the resonant energy and shape of the resonance are seen varying for scattering with different charged states of C60, the pattern of glory oscillation remains the same. When a resonance is swept across one full wavelength of glory oscillation by varying the interaction potential, its “shape parameter” is evolved and revived to that of H-C60 scattering. This work reports that scattering with charged fullerenes can have the same shape parameter of the resonances as in the case of scattering with neutral C60.

Sublimation of Li@C60

Experiments that probe the fundamental properties of endohedral fullerenes often require the preparation of molecular beams or thin films of the neutral molecules. It is challenging to cleanly sublime this class of molecules without producing some thermal degradation. We report combined gas phase and scanning tunnelling microscopy studies that probe the thermal decay of commercial [Li+C60]PF6- in a quartz ampoule and provide treatment conditions that will allow the sublimation of intact, neutral Li@C60 accompanied by a well-characterised component of neutral C60. The decay of the material at appropriate temperatures can be modelled with the assumption of a second order decay process in the oven yielding Arrhenius parameters that can predict the ratio of Li@C60 to C60 in the sublimed material.Graphical abstract

Inter-examiner reliability of radiographic measurements from Open-mouth lateral bending cervical radiographs

BackgroundFollowing head and neck trauma, the involvement of the cranio-cervical junction (CCJ) and its contribution to a patients transition to chronic pain, is poorly understood. The detection of hypermobility in this region is dependent on clinical examination and static imaging modalities such as x-ray, CT and MRI. Sagittal plane hypermobility of the CCJ is evaluated using saggital view, flexion-extension cervical radiographs. Frontal plane hypermobility is typically assessed using lateral bending and open mouth cervical radiographs. Unfortunately there is no established reliability surrounding the use of these measures. This study explores the reliability of radiographic measurements of lateral-bending open-mouth cervical radiographs.MethodsCervical open-mouth lateral-bending X-ray images were collected from 56 different patients between 18 and 60 years of age patients following cervical spine injury. These images were interpreted by two musculoskeletal radiologists and two clinicians (physiatrist and chiropractor), using a standard set of measurements. Measurements included qualitative and quantitative assessments of the amount of asymmetry noted between various osseous landmarks. Reliability statistics were calculated for levels of agreement using kappa coefficients (κ) and Intraclass Correlation Coefficients (ICC) for dichotomous and continuous variables, respectively.ResultsReliability (κ) for qualitative assessments were moderate to substantial for asymmetry of neutral C2 spinous position, dens-lateral mass spacing, and “step off” between the lateral borders of the articular pillars of C2 and C1 lateral mass (κ range = .47–.78). ICC values for the quantitative measurements of dens-lateral mass spacing and “step off” between the lateral borders of the C2 articular pillars and C1 lateral mass were moderate to excellent (ICC range = .56–.97).ConclusionsThe qualitative and quantitative measurements used in this study demonstrated good to excellent inter-examiner reliability. Correlation with clinical findings is necessary to establish the utility of these measurements in clinical practice.

To see C2: Single-photon ionization of the dicarbon molecule.

The C2 carbon cluster is found in a large variety of environments including flames, electric discharges, and astrophysical media. Due to spin-selection rules, assessing a complete overview of the dense vibronic landscape of the C2 + cation starting from the ground electronic state X Σg+1 of the neutral is not possible, especially since the C2 + ground state is of X+ Σg-4 symmetry. In this work, a flow-tube reactor source is employed to generate the neutral C2 in a mixture of both the lowest singlet X Σg+1 and triplet a 3Πu electronic states. We have investigated the vibronic transitions in the vicinity of the first adiabatic ionization potential via one-photon ionization with vacuum ultraviolet synchrotron radiation coupled with electron/ion double imaging techniques. Using ab initio calculations and Franck-Condon simulations, three electronic transitions are identified and their adiabatic ionization energy is determined Ei(a+ 2Πu←X 1Σg +)=12.440(10) eV, Ei(X+ 4Σg -←a 3Πu)=11.795(10) eV, and Ei(a+2Πu ← a3Πu) = 12.361(10) eV. From the three origin bands, the following energy differences are extracted: ΔE(a - X) = 0.079(10) eV and ΔE(a+ - X+) = 0.567(10) eV. The adiabatic ionization potential corresponding to the forbidden one-photon transition X+ ← X is derived and amounts to 11.873(10) eV, in very good agreement with the most recent measurement by Krechkivska et al. [J. Chem. Phys. 144, 144305 (2016)]. The enthalpy of formation of the doublet ground state C2 + cation in the gas phase is determined at 0 K, ΔfH0(0K)(C2 +(Πu2))=2019.9(10) kJ mol-1. In addition, we report the first experimental ion yield of C2 for which only a simple estimate was used up to now in the photochemistry models of astrophysical media due to the lack of experimental data.

Reversible reduction drives anion ejection and C60 binding within an FeII 4L6 cage.

FeII4L6 tetrahedral cage 1 was prepared from a redox-active dicationic naphthalenediimide (NDI) ligand. The +20 charge of the cage makes it a good host for anionic guests, with no binding observed for neutral aromatic molecules. Following reduction by Cp2Co, the cage released anionic guests; subsequent oxidation by AgNTf2 led to re-uptake of anions. In its reduced form, however, 1 was observed to bind neutral C60. The fullerene guest was subsequently ejected following cage re-oxidation. The guest release process was found to be facilitated by anion-mediated transport from organic to aqueous solution. Cage 1 thus employs electron transfer as a stimulus to control the uptake and release of both neutral and charged guests, through distinct pathways.

Local aromaticity mapping in the vicinity of planar and nonplanar molecules.

We report on nucleus-independent magnetic shielding (NICS) scans over the centers of six- and five-membered rings in selected metal phthalocyanines (MPc) and fullerene C60 for more accurate characterization of local aromaticity in these compounds. Detailed tests were conducted on model aromatic molecules including benzene, pyrrole, indole, isoindole, and carbazole and subsequently applied to H2 Pc, ZnPc, Al(OH)Pc, and CuPc. Similar behavior of three selected magnetic probes, Bq, 3 He, and 7 Li+ , approaching perpendicularly the ring centers, was observed. For better visualization of shielding zone over the centers of aromatic rings, we introduced a simple mathematical procedure: the first and second derivatives of scan curves with respect to magnetic probe position enabled their additional examination. It allowed an easier localization of curve minimum and discrimination between areas in space varying by the magnetic field magnitude and to illustrate local aromaticity of two different kinds of rings in MPc with better resolution. Our results supported earlier reports on very low aromaticity indexes of pyrrole ring incorporated into MPc and significant aromaticity of the central macrocycle. No direct dependence between harmonic oscillator model of aromaticity and NICS was observed. Instead, a correlation between position of scan curve minimum and its magnitude were observed. In addition, the NICS values and 3 He chemical shifts in the middle of neutral C60 and C606- anion agreed well with the reported experimental NMR values for He@C60 and He@C606- .

Charged Clusters of C60 and Au or Cu: Evidence for Stable Sizes and Specific Dissociation Channels.

We have doped helium nanodroplets with C60 and either gold or copper. Positively or negatively charged (C60)mMn± ions (M = Au or Cu) containing up to ≈10 fullerenes and ≈20 metal atoms are formed by electron ionization. The abundance distributions extracted from high-resolution mass spectra reveal several local anomalies. The sizes of the four most stable (C60)mAun± ions identified in previous calculations for small values of m and n (m ≤ 2 and n ≤ 2, or m = 1 and n = 3) agree with local maxima in the abundance distributions. Our data suggest the existence of several other relatively stable ions including (C60)2Au3± and (C60)3Au4–. Another feature, namely the absence of bare (C60)2±, confirms the prediction that (C60)2M± dissociates by loss of C60± rather than loss of M. The experimental data also reveal the preference for loss of (charged or neutral) C60 over loss of a metal atom from some larger species such as (C60)3M3+. In contrast to these similarities between Au and Cu, the abundance distributions of (C60)3Aun– and (C60)3Cun– are markedly different. In this discussion, we emphasize the similarities and differences between anions and cations, and between gold and copper. Also noteworthy is the observation of dianions (C60)mAun2– for m = 2, 4, and 6.

Exohedral Addition Chemistry of the Fullerenide Anions C60 2- and C60 ⋅.

A systematic screening study of the exohedral reactivity of the reduced fullerenes (fullerenides) C60 2- and C60 ⋅- is reported. These doubly and singly negatively charged carbon cages were prepared by two-fold reduction of C60 with potassium, leading to K2 C60 , or by in situ monoreduction with the radical anion of benzonitrile PhCN⋅- , respectively. Several series of electrophiles, including geminal and distant dihalides, benzyl bromides, and diazonium compounds, were employed as addition partners. In general, the investigated bromides proved to be the most suitable reaction partners. A series of fullerene adducts and cycloadducts involving either 1,2- or 1,4-addition patterns, depending on the precise architecture and the steric demand of the addends, were synthesized and fully characterized. Some of the reaction products are unprecedented and inaccessible forms of neutral C60 . The fullerenide chemistry presented here closely resembles related reactions of graphenides and carbon nanotubides, which are the most powerful methods for the functionalization of these macromolecular forms of synthetic carbon allotropes (SCAs). Activation of C60 by negative charging represents a little explored concept of fullerene chemistry, providing both new insights of fullerene reactivity itself and new types of exohedral derivatives.

Structural distortions of fullerene C60n (n = 0 to −6) by first principle density functional theory

The anions of C60 fullerene have geometrically multiple distortions. These geometric changes of C60 were directly related to the orbital changes called structural distortion effects. In this study, neutral C60 fullerene and its −1 to −6 anions were optimized by using DFT method. The geometric changes and the electronic properties were also investigated. Unrestricted calculations were applied to investigate the energy gap changes and density of states (DOS) spectrums as well. The electron localization function (ELF) along with the natural bond orbital (NBO) calculations were presented the considerable images from the changes of electron properties of C60 fullerene. The results show that in −5 and −6 anions lost π bonds and also can see creation of non-bonding lone pair in −6 anion. The calculations on the vibrational levels, structural changes such as changes in diameters and dipole moments of C60n (n = 0 to −6) were investigated as well. The most stable spin forms of the optimized C60 structures were chosen to observe structural distortions by using the DFT computational method. For some of the anions the wide changes of forms, energies of the valance orbitals and the energy states were investigated for the low and high spins. Also, the spin channel phenomenon was studied by using the results of DFT-B3LYP/6-31G∗ calculations. The NBO analysis was performed due to its beneficial information in the changes of fullerene electronic system properties for all the anion states in the selected computational level method. The changes of the calculated IR spectra patterns have discussed due to the charge changes of C60n (n = 0 to −6) and on the basis of the structural distortions role (John-Teller effect). A linear equation was obtained by using graph theory (GT) between the energy of HOMO and/or LUMO orbitals and load amount of anions. The DOS spectrums and HOMO and LUMO orbitals in the different discussed spin states show that all fullerene anions have different spin behavior and magnetic specifications, in which anions −2 and −3 anions of C60 act as the spin channels.

The plasma morphology of an asymmetric electrode ablative pulsed plasma thruster

The ablative pulsed plasma thruster (APPT) is a typical form of electric propulsion that is highly suitable for micro-satellites. However, its low performance has been a main drawback. Recently, an asymmetric segmented anode schematic was shown to enhance the performance of APPTs. The improved thrust performance obtained with the use of a segmented anode can potentially enable promising applications in future space tasks. To further understand the physical processes behind a segmented anode APPT, experiments using an ultra-high-speed camera, narrow bandpass filters, and a magnetic probe were conducted with both normal parallel-plate electrodes and a segmented anode on an experimental APPT. Successive images of light emission from C+, neutral C2, and broadband emission reveal the evolution of the plasma morphology on an APPT with a segmented anode. The magnetic field strength profiles show that the inter-electrode plasma propagation velocity of a segmented anode APPT is approximately 19 km s−1, which is slightly lower than that of a normal APPT at 23 km s−1. However, the similar order of magnitude suggests a similar downstream acceleration mechanism between the two. The arc morphology observed in the high-speed images shows that the segmented anode APPT with asymmetric electrodes has a restricted arc attachment point, possibly resulting in stronger arc current density at the anode corner. This should result in higher ionization and ablation when compared with a normal anode APPT. Based on the results here, we hypothesize that the segmented anode APPT may be able to better utilize the restrike energy in the propellant ionization process. This fundamentally changes the physical process behind APPT operation, meaning that the improvements should also be applicable to other APPT designs. It can also be adopted as an additional step in the overall optimization of an APPT design.

Isomeric and Isotopic Effects on the Electronic Spectrum of –He: Consequences for Astronomical Observations of

Abstract Laboratory measurements are reported that enable a more accurate determination of the characteristics of the near-infrared absorptions of below 10 K. These data were obtained by photofragmentation of complexes in a cryogenic trap. Asymmetry in the profiles of the observed 9577 and 9632 Å absorption bands of is caused by the attachment of the weakly bound helium atom to hexagonal or pentagonal faces of . The implication is that the FWHM of the bands in the electronic spectrum of below 10 K is 1.4 Å. The effect of 13C isotopes on the electronic spectrum is experimentally evaluated by measurement of , , and . Data on the 9365 Å absorption band indicate a wavelength shift of about 0.3 Å between the former and latter. This result is consistent with models used to interpret the vibrational isotope effect in the Raman spectrum of neutral C60. The influence of 13C isotopes on the 9348, 9365, 9428, 9577, and 9632 Å diffuse interstellar bands is expected to be minor considering other broadening factors that affect astronomical observations. The presented data also provide more accurate relative intensities of the five interstellar bands attributed to .

A Study on the Origin of the Radical in Fullerene and Graphene

We reported the electron spin resonance (ESR) signal in neutral low band gap semiconductors and C60 in the Li Y., J. Phys. Chem. C 2017, 121, 8579–8588. Herein, further investigation on the origin of the radical of fullerene and its derivatives was conducted, and we proposed an open-shell diradical ground state of C60 and its derivatives for the first time in this work. The radicals of fullerene are usually acknowledged as their impurities or radical cations/anions. Diradical ground states in polycyclic aromatic hydrocarbons including the zethrene family and others with fused five-/six-member rings motivate us to investigate the other potential origin of the radicals of fullerene. C60 has 1812 sets of resonance structures, which is the key factor to stabilize its diradicals. Numerous sets of resonance structures and excellent electron delocalization of graphene play as the key factors in stabilizing its diradicals. The previously claimed ESR-silent C60 after sublimation is due to the four-member ring formation and further self-polymerization. C60 with higher purity exhibited a higher ESR signal intensity, and this further confirmed that the ESR might not come from the impurity. Previously published work confirmed the radical is not from a radical cation/anion; our proposal of the radical of fullerene is reasonable in understanding its basic properties. Moreover, the radical origin of graphene is also proposed similarly.