We derive an exact representation of the exchange-correlation energy within density functional theory (DFT) which spawns a class of approximations leading to correct long-range asymptotic behavior. Using a simple approximation, we develop an electronic structure theory that combines a new local correlation energy (based on Monte Carlo calculations applied to the homogeneous electron gas) and a ...

Using van der Waals-corrected density functional theory and a local chemical bond analysis, we study and explain trends in the binding between CO2 and open-metal coordination sites within a series of two metal-organic frameworks (MOFs), BTT, and MOF-74 for Ca, Mg, and nine divalent transition-metal cations. We find that Ti and V result in the largest CO2 binding energies and show that for these...

Predissociation dynamics of methylamines (CH(3)NH(2) and CH(3)ND(2)) on the first electronically excited states are studied using the slow-electron velocity imaging method to unravel the multi-dimensional nature of the N-H(D) chemical bond dissociation reaction which occurs via tunnelling. The nearly free internal rotation around the C-N bond axis is found to be strongly coupled to the reaction...

Multiconfigurational quantum chemical methods (CASSCF/CASPT2) have been used to study the chemical bond in the actinide diatoms Ac2, Th2, Pa2, and U2. Scalar relativistic effects and spin−orbit coupling have been included in the calculations. In the Ac2 and Th2 diatoms the atomic 6d, 7s, and 7p orbitals are the significant contributors to the bond, while for the two heavier diatoms, the 5f orbi...

in the present work, the structural and electronic properties, and conductivity of (5,5) and (6,6) single walled carbon nanotubes in the ground state have done by using the hartree-fock and density functional theory dft-b3lyp/6-31g* level. delocalization of charge density between the bonding or lone pair and antibonding orbitals calculated by nbo (natural bond orbital) analysis. these methods a...

a theoretical density functional theory (dft) study was performed on a series of the neutral n-phenylthiourea substituents (p-oc2h5, p-ch3, m-ch3, h, p-cl, p-br, m-cl, and p-no2) as the sensor of acetate and fluoride anions. the hydrogen bond character was analyzed as a scale of the sensing activity. it was confirmed that hydrogen bond between the p-no2 derivatives of n-phenylthiourea and fluor...

Density functional theory methods(DFT) and natural bond orbital (NBO) analysis were used to investigate the effects of isomerism and side chain mutation at a microscopic level on the stability, binding energy and NMR/NQR tensors of structural isomers, L- methionylasparagine (Met-Asn) and L- asparagylmethionine (Asn-Met) in the gas phase. The results represented that the isomerism and side chain...

In the present work, the structural and electronic properties, and conductivity of (5,5) and (6,6) Single Walled Carbon Nanotubes in the ground state have done by using the Hartree-Fock and density functional theory DFT-B3LYP/6-31G* level. Delocalization of charge density between the bonding or lone pair and antibonding orbitals calculated by NBO (natural bond orbital) analysis. These methods a...