Fullerene Size Research Articles

W(h)Ither Fullerenes in Medicine? Challenges and Opportunities in Industrial Translation

The fullerenes—C60 and its derivatives in particular—have been lauded for three decades now as having revolutionary potential for next-generation medical applications. These span therapeutics (e.g. enzyme inhibition and photodynamic therapy for treating cancers) and diagnostics (e.g. improved contrast agents for magnetic resonance imaging). But translating this potential beyond academic research studies and into scaled-up production and clinical practice has proved far more elusive than the much-sought-after widespread industrial adoption of graphene.In this talk I will first outline why the fullerenes do indeed offer such promise in these clinical application areas, before providing an exploration of many of the intersecting factors that have contributed to making the clinical translation of fullerene-based therapeutics and diagnostics such a seemingly insurmountable barrier up to this point. These factors include: A uniquely multi-dimensional chemical design space when considering fullerene size and both exohedral and endohedral functionalisation possibilities;The relationship of the above with understanding functionality and safety in vivo;Regulatory requirements pertaining to the above;The presence of unregulated fullerene-based products in the beauty and wellness sector;The fuzzy borderlands between science and pseudoscience that much of the narrative around fullerenes occupies;Loss of funding momentum;Lack of industrial bridges between materials manufacturers and technology developers. After characterising the state of affairs in this way, I will offer some specific suggestions for hope and opportunity as we move into a world where synthesis and testing bottlenecks can be overcome with the help of artificial intelligence and automation, and increased awareness of the diverse properties of different types of nanomaterials changes the regulatory and industrial landscapes. Thus, I hope to provide a case study of how one family of carbon nanomaterials could finally realise its promise of advancing medicine in the Industry 4.0 era.

Controlling Nonlinear Optical Switch of Diarylethene by Changing Sizes of Fullerene: A Theoretical Study

AbstractFullerene is a material with good electrical conductivity and thermal stability, and its size is an important factor to influence its photoelectric property. In this work, effect of fullerene size (C20, C60, and C70) on nonlinear optical (NLO) switchable molecule diarylethene (DAE) was explored. In the aspect of molecular NLO properties, it could be found that the static first hyperpolarizability βtot of Cx‐O (x=20, 60, 70) was larger than that of Cx‐C (x=20, 60, 70), and the βtot difference between open‐ring and closed‐ring structure increased from 19 to 1431 au with the size of fullerene increased. Especially for C70‐DAE, its largest contrast of βtot values between open‐ring and closed‐ring structure suggested its superiority among three groups of NLO switchable complexes. The result could attribute to C70‐O exhibits a strong dipole characteristic, whereas C70‐C displays a weak dipole characteristic. By analyzing dynamic first hyperpolarizability, it could be found large NLO response mainly depended on molecular dipole characteristics. As a result, for C70‐DAE, βHRS of open‐ring structure was still larger than that of closed‐ring structure. However, the dynamic first hyperpolarizability βHRS of open‐ring structure was smaller than that of closed‐ring structure in both C20‐DAE and C60‐DAE. The switching efficiency was reversed.

Stability of [10-12]cycloparaphenylene complexes with pristine fullerenes C76,78,84 and endohedral metallofullerenes M3N@C78,80.

[n]Cycloparaphenylenes ([n]CPPs) are strained macrocycles, comprising only sp2-hybridized carbon atoms. In recent years, [n]CPPs have become of great research interest in the field of supramolecular chemistry since their special structure enables the formation of novel host-guest complexes. In this work, we investigate the gas-phase chemistry of noncovalent complexes of [10-12]CPP with the pristine fullerenes C76/78/84 and the endohedral metallofullerenes (EMFs) Sc3N@D3h-C78, Sc3N@D5h-C80 and M3N@Ih-C80 (M = Sc, Y, Lu, Gd). The [1 : 1] complexes with [10-12]CPP are detected as radical cations. The stability and charge distributions of these complexes are studied using energy-resolved collision-induced dissociation (ER-CID). Our results assess the size complementarity, the influence of fullerene symmetry and size as well as the role of the metal size inside the EMF on the binding affinity and complex stability. Two main trends in complex stability have been found: First, [10-12]CPP form more stable complexes with EMFs than with pristine fullerenes and second, all complexes of EMFs with the C80 skeleton show similar stability despite the different metal clusters encapsulated. Another major finding is the fact that [11]CPP is generally the most suitable host for fullerenes with a C76/78/80/84 skeleton. Considering the charge distributions, we observe the existence of two different fragmentation channels for complexes with EMFs where the radical cation is either located at the CPP or at the EMF: (1) [n]CPP+˙ + EMF and (2) [n]CPP + EMF+˙. This behavior allows a clear distinction of the cage isomers ([11]CPP⊃Sc3N@Ih-C80)+˙ and ([11]CPP⊃Sc3N@D5h-C80)+˙ in the MS2 experiment. The experimental results are accompanied by density functional theory (DFT) calculations of ionization potentials (IPs) and fragmentation energies. The computational results fully confirm the measured order of complex stabilities and explain the prevalence of EMF or CPP signals in the spectra by the trend in ionization potentials.

Synthesis and Characterization of Ionic Li+ @C70 Endohedral Fullerene.

Ion-endohedral-fullerene has attracted growing interest due to the unique electronic and structural characteristics arising from its distinctive ionic nature. Although there has been only one reported ion-encapsulated fullerene, Li+ @C60 , a significant number of fundamental and applied studies have been conducted, making a substantial impact not only in chemistry and physics but also across various interdisciplinary research fields. Nevertheless, studies on ion-endohedral fullerenes are still in their infancy due to the limitations in variety, and hence, it remains an open question how the size and symmetry of fullerene, as well as the motion and position of the encapsulated ion, affect their physical/chemical properties. Herein, we report the synthesis of lithium-ion-endohedral [70]fullerene (Li+ @C70 X- , X=PF6 - and TFSI- ), a novel ionic endohedral fullerene. X-ray crystallography confirmed the encapsulation of Li+ by C70 cage as well as its ion-pair structure stabilized by external TFSI- counter anion. The encapsulated Li+ drastically lowered the orbital energy of the C70 cage by Coulomb interactions but did not affect the orbital energy gap and degeneracy. DFT studies were also performed, which supported the experimentally observed electronic effects caused by the encapsulated Li+ .

The role of domain size and weight ratio of fullerene and non-fullerene acceptors on performance of PM6:Y6: PCBM ternary solar cell

The role of domain size and weight ratio of fullerene and non-fullerene acceptors on performance of PM6:Y6: PCBM ternary solar cell

Rational Design, Stabilities and Nonlinear Optical Properties of Non-Conventional Transition Metalides; New Entry into Nonlinear Optical Materials.

Electronic and nonlinear optical properties of endohedral metallofullerenes are presented. The endohedral metallofullerenes contain transition metal encapsulated in inorganic fullerenes X12Y12 (X = B, Al & Y = N, P). The endohedral metallofullerenes (endo-TM@X12Y12) possess quite interesting geometric and electronic properties, which are the function of the nature of the atom and the size of fullerene. NBO charge and frontier molecular orbital analyses reveal that the transition metal encapsulated Al12N12 fullerenes (endo-TM@Al12N12) are true metalides when the transition metals are Ni, Cu and Zn. Endo-Cr@Al12N12 and endo-Co@Al12N12 are at the borderline between metalides and electrides with predominantly electride characteristics. The other members of the series are excess electron systems, which offer interesting electronic and nonlinear optical properties. The diversity of nature possessed by endo-TM@Al12N12 is not prevalent for other fullerenes. Endo-TM@Al12P12 are true metalides when the transition metals are (Cr-Zn). HOMO-LUMO gaps (EH-L) are reduced significantly for these endohedral metallofullerenes, with a maximum percent decrease in EH-L of up to 70%. Many complexes show odd-even oscillating behavior for EH-L and dipole moments. Odd electron species contain large dipole moments and small EH-L, whereas even electron systems have the opposite behavior. Despite the decrease in EH-L, these systems show high kinetic and thermodynamic stabilities. The encapsulation of transition metals is a highly exergonic process. These endo-TM@X12Y12 possess remarkable nonlinear optical response in which the first hyperpolarizability reaches up to 2.79 × 105 au for endo-V@Al12N12. This study helps in the comparative analysis of the potential nonlinear optical responses of electrides, metalides and other excess electron systems. In general, the potential nonlinear optical response of electrides is higher than metalides but lower than those of simple excess electron compounds. The higher non-linear optical response and interesting electronic characteristics of endo-TM@Al12N12 complexes may be promising contenders for potential NLO applications.

Size distribution of polycyclic aromatic hydrocarbons in space: an old new light on the 11.2/3.3 μm intensity ratio.

The intensity ratio of the 11.2/3.3 μm emission bands is considered to be a reliable tracer of the size distribution of polycyclic aromatic hydrocarbons (PAHs) in the interstellar medium (ISM). This paper describes the validation of the calculated intrinsic infrared (IR) spectra of PAHs that underlie the interpretation of the observed ratio. The comparison of harmonic calculations from the NASA Ames PAH IR spectroscopic database to gas-phase experimental absorption IR spectra reveals a consistent underestimation of the 11.2/3.3 μm intensity ratio by 34%. IR spectra based on higher level anharmonic calculations, on the other hand, are in very good agreement with the experiments. While there are indications that the 11.2/3.3 μm ratio increases systematically for PAHs in the relevant size range when using a larger basis set, it is unfortunately not yet possible to reliably calculate anharmonic spectra for large PAHs. Based on these considerations, we have adjusted the intrinsic ratio of these modes and incorporated this in an interstellar PAH emission model. This corrected model implies that typical PAH sizes in reflection nebulae such as NGC 7023 - previously inferred to be in the range of 50 to 70 carbon atoms per PAH are actually in the range of 40 to 55 carbon atoms. The higher limit of this range is close to the size of the C60 fullerene (also detected in reflection nebulae), which would be in line with the hypothesis that, under appropriate conditions, large PAHs are converted into the more stable fullerenes in the ISM.

The largest fullerene.

Fullerenes are lowest energy structures for gas phase all-carbon particles for a range of sizes, but graphite remains the lowest energy allotrope of bulk carbon. This implies that the lowest energy structure changes nature from fullerenes to graphite or graphene at some size and therefore, in turn, implies a limit on the size of free fullerenes as ground state structures. We calculate this largest stable single shell fullerene to be of size N = 1 × 104, using the AIREBO effective potential. Above this size fullerene onions are more stable, with an energy per atom that approaches graphite structures. Onions and graphite have very similar ground state energies, raising the intriguing possibility that fullerene onions could be the lowest free energy states of large carbon particles in some temperature range.

The nonlinear optical properties and noncovalent interactions of supramolecular Donor−acceptor−donor assemblies between molecular tweezers and fullerenes

The supramolecular donor−acceptor−donor (D−A−D) system were formed between the tweezer and C60 with strong intermolecular charge transfer interactions, which enhance the two-photon absorption (TPA) cross-section. Here, we would use density functional theory method to investigate three effects of molecular structures on the intermolecular interactions and the second order NLO properties of supramolecular complexes, including: (1) the effects of N atom substitution in tweezer (2) the effects of four extra benzene rings in tweezer (3) the effect of fullerene size. It was found that the substitution of N atoms and the addition of the four extra benzene rings to tweezer weakened the intermolecule interactions between fullerene and tweezer, suggesting that they did not enhance the electron-giving capacities of tweezers. While the fullerenes of larger size can form the stronger intermolecule interaction with tweezers.

Molecular dynamics simulation of perforation of graphene under impact by fullerene projectiles

In this paper, molecular dynamics (MD) simulations are employed to study the perforation of graphene under impact by fullerenes of various sizes. The buckling characteristics of fullerenes after impact are classified and discussed. The relative state of C180 projectile and graphene under impact at different velocities is also investigated. We observed that the C180 projectile rebounds at low velocity (V < 4.25 km/s), sticks to graphene at high velocity (4.25 km/s ≤ V ≤ 4.75 km/s), and perforates the graphene at higher velocity (V ≥ 4.75 km/s). It is found that the buckled cap of large-size fullerene formed after impact can better absorb kinetic energy. In addition, different crack modes of graphene after perforation were investigated. The effect of fullerene projectile size and initial velocity on ballistic limit velocity was also clarified. This study provides new implications for the application of large-size fullerenes as impact shields.

Образование и рост фуллеренов и нанотрубок, имеющих Т-симметрию третьего порядка

According to the periodic system of fullerenes, all the fullerenes can be classified into the groups having different symmetry. It is supposed that the fullerenes of one and the same symmetry have similar properties. Before the appearance of the periodic system in 2017 the fullerenes were chosen for study at a random way that instead of ordering the results only increased information entropy. We have studied possible ways of generation and growing the fullerenes, which refer to the group having three-fold T-symmetry. Beginning with cyclopropane C3H6 producing clusters C6, we have obtained elementary fullerenes C6 as well as mini-fullerenes C12, which in their turn have produced the fullerenes from C18 to C48, perfect and imperfect, as well as nanotubes. The basic perfect fullerenes C18, C24, C30, C36, C42 and C48 have the ordinary three-fold symmetry, the intermediate ones having no such symmetry. Their imperfection is connected with extra ‘interstitial’ or carbon dimers, the dimers playing the role of defects. One can define the imperfect fullerenes with defects as the fullerenes having topological three-fold symmetry. We have calculated their shape and energies using Avogadro package and discussed possible reasons of their dependence on a fullerene size and shape. We have found that the fullerenes can be divided into two groups, alive that can grow, and dead which are impotent. Taking into account the results obtained early, allows us to make predictions that the dead fullerenes C24R, C32R, C40R and C48R of three-, four-, five- and six-fold symmetry have the most chance to be found experimentally with comparison of their isomers.

Fullerene–phosphorene–nanoflake nanostructures: Modulation of their interaction mechanisms and electronic properties through the size of carbon fullerenes

In this work, we employed density functional theory modeling to obtain the structure, binding mechanism, and electronic/optical properties of carbon-based interfaces formed by phosphorene nanoflakes and carbon fullerenes (C24 to C70). Fullerenes form stable covalent and non-covalent complexes with phosphorene depending on their molecular size. A continuum solvation model indicates that complexes are stable in solution, independent of the solvent polarity. Two classes of covalent complexes arise by cycloaddition-like reactions (nanobuds): the first class, where short-range effects (charge-transfer and polarization) determine the stability; the second one, where short-range effects decay to avoid steric repulsion, and long-range forces (electrostatics and dispersion) favors the stability. High-size fullerenes (C50–C70) only form non-covalent complexes as experimentally obtained due to strong repulsion at shorter intermolecular distances and lack of dissociation barriers. Fullerenes also act as mild p-dopants for phosphorene, increasing its polar character and ability to acquire induced dipole moments. Moreover, small energy-bandgap (low-size) fullerenes increase the phosphorene metallic character. Fullerenes also act as active sites for orbital-controlled interactions and maximize the phosphorene light absorbance at the UV–Vis region. An outlook of these nanostructures provides practical nanotechnological applications in storage, batteries, sensing, bandgap engineering, and optoelectronics.

Reactivity of Li+@C60@C240 and Photoinduced Charge Shift in Li+ Doped Giant Nested Fullerenes

Over the last years, carbon nano-onions (CNOs) have been in focus in material science research. Apart from its prospective use in solar cells, the number of potential applications of CNOs have grown in the last decades. Among them, we can mention their application in gas storage processes, solid lubrication, or heterogeneous catalysis, and also as electrode materials in capacitors, anode materials in lithium-ion batteries, catalyst support in fuel cells, or electro-optical devices. From the analysis of the polarizability of CNOs, it was concluded that CNOs behave as near perfect nanoscopic Faraday cages.[1] If CNOs behave as ideal Faraday cages, the reactivity of the C240 cage should be the same in Li+@C240 and Li+@C60@C240. In the first part of this work, we have analyzed the Diels-Alder reaction of cyclopentadiene to the free C240 cage and the C60@C240 CNO together with their Li+-doped counterparts using density functional theory (DFT). We find that in all cases the preferred cycloaddition is on bond [6,6] of type B of the C240 cage. From the comparison between the reactivity of Li+@C240 and Li+@C60@C240, we conclude that C60@C240 does not act as a perfect Faraday cage.[2] In the second part of this work, we perform a systematic study of excited state properties of six double-layered Li+ doped fullerenes of Ih symmetry: [Li@C60@C240]+, [Li@C60@C540]+, [Li@C60@C960]+, [Li@C240@C540]+, [Li@C240@C960]+ and [Li@C540@C960]+. On the basis of TDDFT calculations, we show that the long-wave absorption by the Li+ doped species leads to charge transfer (CT) between the inner and the outer shells unlike their neutral double-layered precursors. The CT energy depends strongly on the size of the concentric fullerenes and it can easily be tuned by varying both the encapsulated metal ion and the size of the shells. Two types of low-lying excited states are identified (1) capacitor-like structures, as Li+@C60 -@C240 +, with alternating positive and negative charges, and (2) states, where the positive charge is delocalized over the outer shell, as in Li@C240@C540 +.[3] References [1] R. R. Zope, J. Phys. B: At. Mol. Opt. Phys. 41 (2008) 41, 085101; [b] R. R. Zope, S. Bhusal, L. Basurto, T. Baruah and K. Jackson, J. Chem. Phys. 143 (2015) 084306.[2] A. J. Luque-Urrutia, A. Poater and M. Solà. Chem. Eur. J., 26 (2020) 804-808.[3] A. J. Stasyuk, O. A. Stasyuk, M. Solà and A. A. Voityuk. J. Phys. Chem. C 123 (2019) 16525-16532. Figure 1

Interaction of curcumin molecule with fullerene material by simulation method

The designs of target-drug delivery systems are attractively concerned due to their efficacy and safety. Fullerene is the first symmetrical carbon nanomaterial invented in the world. Due to the special properties of fullerene, it is an emergent topic in nanomaterials in recent years. Many experimental studies used this material to form the drug-carrier system and have shown a significant improvement in the pharmacokinetic properties of the active substance. Curcumin is a natural compound extracted from turmeric, with many pharmacological properties such as antiviral, antibacterial, and impact on cancer cells, etc. However, curcumin's pharmacological properties are hardly clinically demonstrated due to its water-solubility. A fullereo-curcuminoid derivative to HIV viruses and cancer cells was created, in which curcumin is out-bound to fullerene. HIV antiviral properties showed only moderate efficiency, and no anti-cancer effect was observed. Another disadvantage of the out-bound fullereo-curcuminoid derivative is that it is hard to control the number of curcumin-derivative molecules that bind out-surfaced fullerene, which is a critical problem we need to deal with since curcumin overdose causes side effects to the digestive system, skin, or headache. For the above reasons, we decided to conduct this research, focusing on the computational approach of in-bound fullereo-curcuminoid derivative systems for drug delivery, with adequate fullerene size to encapsulate curcumin molecules. This proposed model is promising not only to create a better anti-solvent shield for the curcumin molecule throughout the delivery path to the target cells but also to manipulate the curcumin dose since the fullerene shield may increase the efficiency of curcumin carrying. This research uses the computational simulation method to investigate the epidermal growth factor (EGF) receptor binding and the physicochemical parameters of the curcumin molecule encapsulated in fullerene. The density functional theory (DFT) calculation is conducted to observe the electrical and energetic properties of the curcumin-fullerene encapsulation system. The obtained system is then docked with the target receptor. After that, the size-modified defected gap will be created on the fullerene surface in the release process of the curcumin out of the fullerene. To interact with the target residues on the receptor will be observed by using MD simulation and their interaction stabilization.

Polyhydroxy Fullerene‐loaded ZIF‐8 Nanocomposites for Better Photodynamic Therapy

Photodynamic therapy (PDT) has been received broad attentions as a cancer treatment, and fullerenes are potential photosensitizer owing to their unique electronic structures. However, fullerenes show insolubility in water for the special structure, which will induce aggregation to hinder the production of reactive oxygen species (ROS). Furthermore, the size of fullerenes is not conducive to reach the tumors through the enhanced permeability and retention (EPR) effect. Herein, a polyhydroxy fullerene‐loaded metal‐organic framework is designed and prepared to address the mentioned problems encountering with fullerenes as photosensitizers. The nanocomposite PHF@ZIF‐8, which is synthesized by a simple one‐pot method, displays great biocompatibility and outstanding photodynamic performance under the 448 nm laser irradiation. This work provides strong evidence for PHF@ZIF‐8 as a promising photosensitizer candidate.

Interaction of dopants and functional groups adsorbed on the carbon fullerenes: Computational study

Abstract We apply density functional theory to study the effective interaction between dopant atoms (B, N, Si, P) and functional groups (H, F, Cl, OH) on the surface of carbon fullerenes. Both dopant atoms and functional groups strongly interact through the carbon cage even in diametrically opposite positions. Interaction energies distribute in a wide range from 0.1 to 2 eV and non-monotonically depend on fullerene size and distance between dopants or functional groups. Such interaction cannot be described as a simple Coulomb repulsion or sum of dopants binding energies and cage strain energy. We identify some general trends in relative positions of dopants or functional groups in low-energy isomers. Para position of two functional groups is the most feasible for C60 and larger cages. For lower fullerenes, ortho or other spaced positions may be more preferable. The interaction of foreign atoms embedded into the carbon cages is more complicated. The best relative positions intricately depend on the cage size and chemical nature of dopants. As a rule, ortho and para locations are feasible for C60 and larger cages. However, some exceptions are observed. The effect of thermal vibrations on the considered interactions in doped or functionalized fullerenes is negligible in the temperature range from 300 to 1000 K.

Monte Carlo simulations of hydrogen adsorption in fullerene pillared graphene nanocomposites

ABSTRACTThe objective of this study is to investigate the hydrogen storage performances of three-dimensional periodic fullerene pillared graphene nanocomposites (FPGNs) consisting of covalently bonded fullerene units between graphene layers. Different forms of fullerenes were used as pillars to adjust porosity and enhance the hydrogen storage capacities of the proposed structures. The gravimetric and volumetric hydrogen uptakes of FPGNs were investigated via grand canonical Monte Carlo calculations under both low- and high -pressure (i.e. 0.01–100 bars) and different thermal (i.e. 77 and 298 K) loading conditions. The simulation results showed that a considerable enhancement in hydrogen adsorption performance could be achieved with the appropriate selection of fullerene size and loading conditions. The simulation results revealed that the FPGNs could uptake 10.3 wt.% hydrogen at 77 K. In addition, the deliverable hydrogen storage capacity of FPGNs could overpass 7.8 wt.% for the charge at 77 K, 100 bar and discharge at 160 K, 5 bar conditions which emphasises the potential of the proposed structures as future ultra-lightweight hydrogen storage media.

(Invited) Reactivity of Li+@C60@C240 and Photoinduced Charge Shift in Li+ Doped Giant Nested Fullerenes

Over the last years, carbon nano-onions (CNOs) have been in focus in material science research. Apart from its prospective use in solar cells, the number of potential applications of CNOs have grown in the last decades. Among them, we can mention their application in gas storage processes, solid lubrication, or heterogeneous catalysis, and also as electrode materials in capacitors, anode materials in lithium-ion batteries, catalyst support in fuel cells, or electro-optical devices. From the analysis of the polarizability of CNOs, it was concluded that CNOs behave as near perfect nanoscopic Faraday cages.[1] If CNOs behave as ideal Faraday cages, the reactivity of the C240 cage should be the same in Li+@C240 and Li+@C60@C240. In the first part of this work, we have analyzed the Diels-Alder reaction of cyclopentadiene to the free C240 cage and the C60@C240 CNO together with their Li+-doped counterparts using density functional theory. We find that in all cases the preferred cycloaddition is on bond [6,6] of type B of the C240 cage. From the comparison between the reactivity of Li+@C240 and Li+@C60@C240, we conclude that C60@C240 does not act as a perfect Faraday cage.[2] In the second part of this work, we perform a systematic study of excited state properties of six double-layered Li+ doped fullerenes of Ih symmetry: [Li@C60@C240]+, [Li@C60@C540]+, [Li@C60@C960]+, [Li@C240@C540]+, [Li@C240@C960]+ and [Li@C540@C960]+. On the basis of TDDFT calculations, we show that the long-wave absorption by the Li+ doped species leads to charge transfer (CT) between the inner and the outer shells unlike their neutral double-layered precursors. The CT energy depends strongly on the size of the concentric fullerenes and it can easily be tuned by varying both the encapsulated metal ion and the size of the shells. Two types of low-lying excited states are identified (1) capacitor-like structures, as Li+@C60 -@C240 +, with alternating positive and negative charges, and (2) states, where the positive charge is delocalized over the outer shell, as in Li@C240@C540 +.[3] References [1] R. R. Zope, J. Phys. B: At. Mol. Opt. Phys. 41 (2008) 41, 085101; [b] R. R. Zope, S. Bhusal, L. Basurto, T. Baruah and K. Jackson, J. Chem. Phys. 143 (2015) 084306.[2] A. J. Luque-Urrutia, A. Poater and M. Solà. Submitted for publication.[3] A. J. Stasyuk, O. A. Stasyuk, M. Solà and A. A. Voityuk. J. Phys. Chem. C 123 (2019) 16525-16532. Figure 1

Two-dimensional two-photon absorptions and third-order nonlinear optical properties of Ih fullerenes and fullerene onions.

The third order static and dynamic nonlinear optical (NLO) responses of Ih symmetry fullerenes (C60, C240, and C540) and fullerene onions (C60@C240 and C60@C240@C540) are predicted using the ZINDO method and the sum-over-states model. The static second hyperpolarizability of Ih symmetry fullerenes increases exponentially with fullerene size [from 10.00 × 10-34 esu in C60 to 3266.74 × 10-34 esu ≈ γ0(C60) × 92.63 in C540]. The external fields of strong third order NLO responses of Ih symmetry fullerenes change from ultra-violet (C60) to the visible region (C540) as the fullerene size increases. The outer layer fullerene in the fullerene onions has dominant contributions to the third order NLO properties of the fullerene onions, and the inter-shell charge-transfer excitations have conspicuous contributions to the third order NLO properties. The two-dimensional two-photon absorption spectra of C60 and C240 show that those fullerenes have strong two-photon absorptions in the visible region with short wavelength and in the ultra-violet region.

Negative ion formation in fullerene molecules C44, C74, C100, C124 and C136: determination of their electron affinities

SynopsisHere we investigate through the electron elastic total cross sections (TCSs) calculations the variation of the electron affinity (EA) with the fullerene size from C44 to C136 and contrast their EAs with that of C60. The TCSs are found to be characterized generally by ground, metastable and excited anionic formation during the collisions. The extracted ground state anionic binding energies for C44, C74, C100, C124 and C136 are 3.25eV, 4.03eV, 3.67eV, 3.06 eV and 3.75eV, respectively. These corresponding to the fullerenes EAs demonstrate their wide variation.