By combining variational Monte Carlo (VMC) and complete-basis-set limit Hartree-Fock (HF) calculations, we have obtained near-exact correlation energies for low-density same-spin electrons on a three-dimensional sphere (3-sphere), i.e., the surface of a four-dimensional ball. In the VMC calculations, we compare the efficacies of two types of one-electron basis functions for these strongly corre...

In the near future, material and drug design may be aided by quantum computer assisted simulations. These have potential to target chemical systems intractable most powerful classical computers. However, resources offered contemporary computers are still limited, restricting simulations very simple molecules. order rapidly scale up more interesting molecular systems, we propose embedding of ele...

Fragment methods have been widely studied for computing energies and forces, but less attention has been paid to nonenergetic properties. Here we extend the electrostatically embedded many-body (EE-MB) method to the calculation of cluster dipole moments, dipole moments of molecules in clusters, partial atomic charges, and charge transfer, and we test and validate the method by comparing to resu...

Searching for heavy fermion (HF) states in non-f-electron systems becomes an interesting issue, especially in the presence of magnetism, and can help explain the physics of complex compounds. Using angle-resolved photoemission spectroscopy, scanning tunneling microscopy, physical properties measurements, and the first-principles calculations, we observe the HF state in a 3d-electron van der Waa...

A new method for constructing efficient basis functions for f variational calculations of quantum mechanical rearrangements is presented and tested. With this method, using the same contracted basis functions for all channels in a given vibrational manifold, we can obtain reactive transition probabilities for F + H, H + HF(u’), where v’is the final vibrational state, that are accurate to 0.01 a...

13C NMR spectra of molecules containing one or two benzene rings linked with CH=CH2, CH=CH (transor cis-), C C and CH=N groups revealed the existence of long range deuterium isotope effects on 13C chemical shifts. It was found that deuterium isotope effects over six bonds (6D) are related to the conformation of investigated molecules. Molecular torsional angles were calculated by ab initio HF/6...

In this letter, we report the singlet ground state structure of the full carotenoid peridinin by means of variational Monte Carlo (VMC) calculations. The VMC relaxed geometry has an average bond length alternation of 0.1165(10) Å, larger than the values obtained by DFT (PBE, B3LYP, and CAM-B3LYP) and shorter than that calculated at the Hartree-Fock (HF) level. TDDFT and EOM-CCSD calculations on...

Results of detailed calculations for SrTiOs (100) surface relaxation and the electronic structure for the two different terminations (SrO and TiO2) are discussed. These are based on ab initio Hartree-Fock (HF) method with electron correlation corrections and Density Functional Theory (DFT) with different exchange-correlation functionals, including hybrid (B3PW, B3LYP) exchange techniques. Resul...

In this study electrophilic affinities were calculated at all reactive positions of azulene in electrophilic aromatic substitutions. Structures of cationic intermediates and products were optimized at HF/6-31+G* and B3LYP/6-31+G** levels of theory, and single point calculations were carried out at MP2/6-31+G**//B3LYP/6-31+G** for total energy. NICS calculations, activation energies and relative...