As it can clearly be observed in Figure 1a and 2a in the paper, the total coverage of the biggest species (in this case k = 6) has a maximum and later decreases to a limit value. This behavior is known as adsorption preference reversal (APR) and has also been observed in theoretical calculations and Monte Carlo simulations [1, 2]. The APR phenomenon usually is attributed to presence of repulsiv...

In this work, we study the structural and electronic properties of CX(BN)Y nanotubes, varying CX concentration in BN base structure. The developed work was done combining semiempirical, density functional theory (DFT) Green’s function calculation methods. first part, shown by structure energies that distribution B − C, C N, chemical bonds greatly influence stabilization nanotubes integration ca...

Oscillator strengths for excitations of neutral selenium and tellurium from the ground state are calculated using a semiempirical analytic independent-particle-model. The results are compared to experimental and theoretical data.

The preferred orientations around the internucleotide P-0(3’)(0’) and P-O(5)(w) bonds of the phosphodiester which link the successive nucleotide residues are crucial in discerning the helical as well as nonhelical bend conformations of nucleic acids and polynucleotides. Experimental investigations other than the single-crystal x-ray diffraction methods are unable to provide directly information...

We investigate possible improvements in the accuracy of semiempirical quantum chemistry (SQC) methods through the use of machine learning (ML) models for the parameters. For a given class of compounds, ML techniques require sufficiently large training sets to develop ML models that can be used for adapting SQC parameters to reflect changes in molecular composition and geometry. The ML-SQC appro...

Benchmark calculations of proton affinities and gas-phase basicities of molecules most relevant to biological phosphoryl transfer reactions are presented and compared with available experimental results. The accuracy of proton affinity and gas-phase basicity results obtained from several multi-level model chemistries (CBS-QB3, G3B3, and G3MP2B3) and density-functional quantum models (PBE0, B1B9...

Approximate electronic trial wave function taken as the antisymmetrized product of strictly localized geminals (APSLG) is implemented for semiempirical analysis of molecular electronic structure of “organic” compounds and for calculations of their heats of formation. This resulted in an O(N)-scaling method. Using the MINDO/3 form of the semiempirical Hamiltonian with reparameterized βAB values ...

We present a new implementation of continuum solvation models for semiempirical Hamiltonians that allows the description of environmental effects on very large molecular systems. In this approach based on a domain decomposition strategy of the COSMO model (ddCOSMO), the solution to the COSMO equations is no longer the computational bottleneck but becomes a negligible part of the overall computa...

This essay provides a perspective on several issues in valence bond theory: the physical significance of semilocal bonding orbitals, the capability of valence bond concepts to explain systems with multireferences character, the use of valence bond theory to provide analytical representations of potential energy surfaces for chemical dynamics by the method of semiempirical valence bond potential...

An exploratory semiempirical Hamiltonian (PM3BP) is developed to model hydrogen bonding in nucleic acid base pairs. The PM3BP Hamiltonian is a novel reparametrization of the PM3 Hamiltonian designed to reproduce experimental base pair dimer enthalpies and high-level density-functional results. The parametrization utilized a suite of integrated nonlinear optimization algorithms interfaced with a...