Size-dependent polarizabilities and van der Waals dispersion coefficients of fullerenes from large-scale complex polarization propagator calculations.

Manuel Brand,Zilvinas Rinkevicius,Xin Li,Wissam A Saidi,Karan Ahmadzadeh,Patrick Norman

doi:10.1063/5.0040009

Abstract

While the anomalous non-additive size-dependencies of static dipole polarizabilities and van der Waals C6 dispersion coefficients of carbon fullerenes are well established, the widespread reported scalings for the latter (ranging from N2.2 to N2.8) call for a comprehensive first-principles investigation. With a highly efficient implementation of the linear complex polarization propagator, we have performed Hartree-Fock and Kohn-Sham density functional theory calculations of the frequency-dependent polarizabilities for fullerenes consisting of up to 540 carbon atoms. Our results for the static polarizabilities and C6 coefficients show scalings of N1.2 and N2.2, respectively, thereby deviating significantly from the previously reported values obtained with the use of semi-classical/empirical methods. Arguably, our reported values are the most accurate to date as they represent the first ab initio or first-principles treatment of fullerenes up to a convincing system size.

Highlights

Ever since its most prominent member C60 was first characterized in 1985,1 the remarkable family of carbon fullerenes has gained increasing interest among both the experimental and theoretical communities.2–4 Located in the realm between molecular and nanostructural materials, the properties of fullerenes vary with size, shape, and structure, making them appealing for a wide range of nanotechnological applications such as sensing, photovoltaics, and electronics
An efficient first-principles computational scheme to obtain dispersion coefficients has been established using the linear complex polarization propagator (CPP) method,18–20 where the molecular polarizabilities entering into the Casimir–Polder integral are directly evaluated on the imaginary frequency axis
As a demonstration of the capability of this software, we extend the scope of systems to be treated with the CPP method by performing calculations of static polarizabilities and C6 dispersion coefficients for carbon fullerenes up to C540

Summary

INTRODUCTION

Ever since its most prominent member C60 was first characterized in 1985,1 the remarkable family of carbon fullerenes has gained increasing interest among both the experimental and theoretical communities. Located in the realm between molecular and nanostructural materials, the properties of fullerenes vary with size, shape, and structure, making them appealing for a wide range of nanotechnological applications such as sensing, photovoltaics, and electronics. The cage-like structure with all sp2-hybridized carbon atoms located at the surface leads to delocalized π-electron densities with significant curvature effects, in particular, for fullerenes with smaller diameter Due to their closed structure, the attractive interaction between neutral fullerene pairs is dominated by dispersive long-range contributions.. An efficient first-principles computational scheme to obtain dispersion coefficients has been established using the linear complex polarization propagator (CPP) method, where the molecular polarizabilities entering into the Casimir–Polder integral are directly evaluated on the imaginary frequency axis. Application of this procedure to a set of carbon fullerenes ranging from C60 to C84 revealed anomalous size-dependencies and scalings with respect to the number of carbon atoms N. After affirmation of the integrity of the applied approach, we establish reference data for the scalings of these properties with respect to system size

METHODOLOGY

COMPUTATIONAL DETAILS

Computational protocol assessment

Property size-dependencies

C60 C70 C100 a C180 C240 C540

CONCLUSIONS