Topological analysis of steric and relaxation deformation densities

Evaluation of Charge and Energy Storage in Molecular Nanocapacitors

A model is presented herein for the evaluation of stored charge and energy in molecular-scale capacitors composed of parallel nanosheets. In this model, the nanocapacitor is exposed to an external electric field, and the charging process is considered as a three-stage mechanism, including isolated, exposed, and frozen stages, where each stage possesses its own Hamiltonian and wavefunction. In this way, the third stage's Hamiltonian is the same as that of the first stage, while its wavefunction is frozen to that of the second stage, and consequently, stored energy can be calculated as the expectation value of second stage's wavefunction with respect to the first stage's Hamiltonian. Electron density is then integrated over half-space, i.e., the space separated by a virtual plane located at the middle and parallel to electrodes, to reveal stored charge on nanosheets. The formalism is applied to two parallel hexagonal graphene flakes as nanocapacitor's electrodes, and results are compared with experimental values of similar systems.

Block deformation analysis: Density matrix blocks as intramolecular deformation density

Block deformation analysis as deformation density of atomic orbitals is introduced to analyze intramolecular interactions. In this respect, density matrix blocks in terms of natural atomic orbitals are employed to find interacting and noninteracting multicenter subsystem and extract the corresponding deformation density. Eigenanalysis of this deformation density is performed to result eigenvalues and eigenorbitals as displaced charge due to the intramolecular interaction and orbital space responsible for charge reorganization, respectively, that possesses advantages of other methods, simultaneously. It is applied to several small molecules, different types of carbon allotropes including zero-, one-, and two-dimensional nanostructures, and challenging systems such as ortho-hydrogen atoms in planar biphenyl. Results highly correlate with delocalization and Wiberg bond indices and show that eigenvalues of block deformation analysis deserved to be considered as bonding index.