Ab Initio Calculations of the Spin-half Xy Model
نویسنده
چکیده
In this article, the correlated basis-function (CBF) method is applied for the first time to the quantum spin-half XY model on the linear chain, the square lattice, and the simple cubic lattice. In this treatment of the quantum spin-half XY model a Jastrow ansatz is utilised to approximate the ground-state wave function. Results for the ground-state energy and the sublattice magnetisation are presented, and evidence that the CBF detects the quantum phase transition point in this model is also presented. The CBF results are compared to previous coupled cluster method (CCM) results for the spin-half XY model, and the two formalisms are then compared and contrasted. In this paper we consider the T = 0 properties of the quantum spin system known as the spin-half XY model, described by the Hamiltonian
منابع مشابه
High level Ab inito bench mark computaions on weak interactions (H2)2 dimer revisited
The Potential Energy Surface PES of (H2)2 dimer has been investigated, using five simple rigid rotor models. These models are called: head to head, symmetric side to side, L , steplike and T model. All calculations were done at two levels of ab initio methods: MP2(Full) and QCISD (T,Full) using cc-pVTZ basis set at singlet state of spin multiplicity. The results of scanning PES were then fitte...
متن کاملConformational analysis of N- and C-terminally protected tripeptide model glycyl-isoleucine-glycyl: An ab initio and DFT study
An ab initio and density functional theory (DFT) study about conformational analysis of tripeptide model HCO−GLY−L−ILE−GLY−NH2 is presented. The tripeptide was scanned about initial, central, and final residues, separately while for every scanning procedure the two other residues had been kept in the β conformation and side chain (SC) dihedral angles were maintained on the gauche− (g‾) state (χ...
متن کاملpKa predictions of some aniline derivatives by ab initio calculations
: In this work, different levels of theory containing HF, B3LYP, and MP2 with different basis sets such as 6-31G, 6-31G*, 6-311G, 6-311+G, 6-31+G*, 6-31+G are used to predict relative acidity constants of some aniline derivatives. Three different kinds of radii containing UAHF, Bondi, and Pauling are used to study how cavity forms change acidity constants. In all cases, DPCM model is used to si...
متن کاملAB Initio Calculations of NMR Spectra for H20114C9N4 As A New Nanosemiconductor Molecule
BCN compounds have been researched theoretically and experimentally widely. In this paper, weintroduce the theoretical prediction of ternary B-C-N compounds. NMR spectroscopy was employedextensively to study these ternary nanostructures. We discuss the utilization of chemical shiftinformation as well as ab initio calculations of nuclear shielding for H20134C9N4 structuredetermination. We calcul...
متن کاملResponse of semi-empirical and AB initio methods to angle strain and conjugation effects in (Z,Z,Z)-Cycloocta-1,3,5-triene
The results of MNDO, AM1 and PM3 semi-empirical calculations and HF/6-31G*, MP/6-31G*, MP2/6-311+G**, and B3LYP/6-311G** and QCISD/6-31G* ab initio methods for angle strain and conjugation effects in twist-boat, boat, and half-chair geometries of (Z,Z,Z)-cycloocta-1,3,5-triene indicate that all methods, except PM3, predict wrong ordering of the conformations.
متن کامل