The unrestricted complete active space self-consistent field (UCASSCF) function is defined, and a proof that a UCASSCF eigenfunction of the spin operator S[sup 2] is a CASSCF function is given. The spin-contamination for an unrestricted Hartree-Fock (UHF) function is evaluated by using Araki...
molecular nuclear couplingmolecular orbitals calculationsSCF calculations/ spin-unrestricted MC SCF calculationnuclear spin-spin coupling constantsHCN moleculeUHF MC SCF methodFermi contact contributionThe UHF MC SCF method is used to calculate the Fermi contact contribution to the nuclear spin-spin coupling...
acollar floating 衣领漂浮[translate] aPlease consider specifying a different charge, or choosing a spin unrestricted calculation 请考虑指定不同的充电或者选择旋转无限制的演算[translate]
ChemInform Abstract: A STUDY OF RADIATION-INDUCED FREE RADICALS IN THYMINE BY SPIN-UNRESTRICTED MOLECULAR ORBITAL CALCULATIONSintermediates (and their reactions)doi:10.1002/chin.197730109A.B.HEIBERGH.H.JENSENChemischer Informationsdienst
ChemInform Abstract: A SPIN-UNRESTRICTED MO STUDY OF THE DONOR AND ACCEPTOR STATES OF CARBAZOLEstructure (organic substances)doi:10.1002/chin.197803086R.W.BIGELOWChemischer Informationsdienst
Spin-restricted and unrestricted post-Hartree鈥擣ock calculations were carried out for clusters of triplet methylene and nitroxide radicals. The UHF-based methods such as UMP and QCISD followed by approximate spin projection provide reasonable energy differences between the high-and low-spin states of ...
A continuum limit treatment of planar spin chains with arbitrary S is presented. The difference between integer and half-integer spins is emphasised. While isotropic half-integer spin chains are gapless,and have power-law decay of correlations at T = 0 with exponent eta = 1, integer spin syst...
spin contaminationunrestricted Hartree-Fockdiatomic moleculesdissociation energiescorresponding orbitalsA simple approach for improving the energy and quality of the unrestricted Hartree鈥揊ock (UHF) approximation is presented. Starting from the UHF Slater determinant (SD), we extract eigenstates of S 2 by...
A method is developed to study in detail the contaminating spin components in UHF calculations for free radicals. Applications are made to those cases previously reported in which normal parametrisation of PPP UHF calculations lead to values of 〈S 2 〉 which increase on annihilation of the contam...
UHFAA (unrestricted Hartree-Fock incorporating the annihilation of the quartet spin component) calculations of the spin densities have been made for the cation and anion radicals of two non-alternant hydrocarbons, acepleiadylene (I) and acenaphth [1, 2 (a)] acenaphthylene (II). Effect of ...