Most ab initio calculations on fullerene molecules have been carried out on the basis of the
paradigm of the Hückel model. This is consistent with the restricted nature of the …

We apply the projected Hartree-Fock theory (PHF) for approximating ground states of
Heisenberg spin clusters. Spin-rotational, point-group, and complex-conjugation symmetry …

Recent work on approximating ground states of Heisenberg spin clusters by projected
Hartree–Fock theory (PHF) is extended to a cluster-based ansatz (cPHF). Whereas PHF …

A detailed variational resonance valence bond (RVB) study is performed for the S= 0 ground
state of the C 60 molecule in the framework of the Heisenberg model. It is shown that the 12 …

We report an extensive tabulation of several important topological invariants for all the
isomers of carbon (5, 6)-fullerenes Cn with n= 52–70. The topological invariants (including …

We calculate the electronic properties of the tJ model on a C 60 molecule using the density-
matrix renormalization group and show that Hund's first rule is violated and that for an …

We investigate the solution of a recently proposed [J. Chem. Phys. 117, 9977 (2002)]
improved valence bond model in a basis of Kekulé functions. The model, which has the form …

Electronic energies are calculated for a Hubbard model on the C 60 molecule using
projector quantum Monte Carlo (QMC) methods. The calculations are performed to an …

A detailed analysis of the nature of the π-VB singlet ground state in terms of multiply excited
resonance valence bond (RVB) wavefunctions is presented for some carbon fullerenes in …

The earliest known examples of quantum superposition were found in organic chemistry—in
molecules that “resonate” among multiple arrangements of π-bonds. Small molecules such …