Reply to Comment on "Multiple locations of boron atoms in the exohedral and endohedral C60 fullerene" by J. Xu and G.-L. Hou

TL;DR

This paper defends the authors' use of HF-MP2 calculations over DFT for determining ground state structures of boron-doped fullerenes, highlighting methodological differences and the subtle energy balance affecting results.

Contribution

It demonstrates that HF-MP2 methods can provide reliable ground state confirmations, challenging the superiority of DFT in this context.

Findings

HF-MP2 results align with some DFT results, but not all.

Choice of exchange-correlation functional affects DFT ground state predictions.

Polarization functions do not alter HF ground state confirmations.

Abstract

In three out of five cases considered in our work, DFT calculations presented by Xu and Hou in their Comment give the same ground state confirmations. On the other hand, depending on the choice of the exchange-correlation functional, the geometry optimization within DFT results in different ground state confirmations for B@C60 and B60, Table I of the Comment. Therefore, the energy balance between nearest confirmations in these molecular complexes is subtle, and various methods can give different ground state structures. Consequently, the results of our method - the Hartree-Fock (HF) approach with the second order M{\o}ller-Plesset perturbation theory (MP2) - should be compared with the DFT results on equal ground, we cannot agree that the DFT method used in the Comment is superior to HF-MP2. In the Reply, we also present additional HF calculations with the 6-31G* basis set (used in the Comment for the geometry optimization) to show that the polarization functions do not change the ground state confirmations obtained by us earlier at the HF/6-31G level.