All-electron quantum Monte Carlo calculations for the noble gas atoms He to Xe (2008)
Ma, A., Drummond, N. D., Towler, M. D., Needs, R. J.
We report all-electron variational and diffusion quantum Monte Carlo (VMC and DMC) calculations for the noble gas atoms He, Ne, Ar, Kr, and Xe. The calculations were performed using Slater-Jastrow...
Scheme for adding electron-nucleus cusps to Gaussian orbitals (2008)
Ma, A., Towler, M. D., Drummond, N. D., Needs, R. J.
A simple scheme is described for introducing the correct cusps at nuclei into orbitals obtained from Gaussian basis set electronic structure calculations. The scheme is tested with all-electron...
Inhomogeneous backflow transformations in quantum Monte Carlo calculations (2008)
Lopez-Rios, P., Ma, A., Drummond, N. D., Towler, M. D., Needs, R. J.
An inhomogeneous backflow transformation for many-particle wave functions is presented and applied to electrons in atoms, molecules, and solids. We report variational and diffusion quantum Monte...
Quantum Monte Carlo study of the Ne atom and the Ne+ ion (2008)
Drummond, N. D., Rios, P. Lopez, Ma, A., Trail, J. R., Spink, G., Towler, M. D., ...
We report all-electron and pseudopotential calculations of the ground-stateenergies of the neutral Ne atom and the Ne+ ion using the variational and diffusion quantum Monte Carlo (DMC) methods. We...
Diffusion quantum Monte Carlo study of three-dimensional Wigner crystals (2008)
Drummond, N. D., Radnai, Z., Trail, J. R., Towler, M. D., Needs, R. J.
We report diffusion quantum Monte Carlo calculations of three-dimensional Wigner crystals in the density range r_s=100-150. We have tested different types of orbital for use in the approximate wave...
Jastrow correlation factor for atoms, molecules, and solids (2008)
Drummond, N. D., Towler, M. D., Needs, R. J.
A form of Jastrow factor is introduced for use in quantum Monte Carlo simulations of finite and periodic systems. Test data are presented for atoms, molecules, and solids, including both all-electron...
Interpretation of Hund's multiplicity rule for the carbon atom (2004)
Hongo, Kenta, Maezono, Ryo, Kawazoe, Yoshiyuki, Yasuhara, Hiroshi, Towler, M. D., Needs, R. J.
Hund's multiplicity rule is investigated for the carbon atom using quantum Monte Carlo methods. Our calculations give an accurate account of electronic correlation and obey the virial theorem to high...
Diamond and $\beta$-tin structures of Si studied with quantum Monte Carlo calculations (2004)
Alfè, D., Gillan, M. J., Towler, M. D., Needs, R. J.
We have used diffusion quantum Monte Carlo (DMC) calculations to study the pressure-induced phase transition from the diamond to $\beta$-tin structure in silicon. The calculations employ the...
Stability and aromaticity of B i N i rings and fullerenes (2003)
Jon M. Matxain, Jesus M. Ugalde, M. D. Towler, R. J. Needs
B i N i clusters have been studied using the hybrid B3LYP density functional and diffusion quantum Monte Carlo (DMC) methods. Different cluster families have been characterized for each cluster size...
Oxygen-stripes in La0.5Ca0.5MnO3 from ab initio calculations (2003)
Ferrari, V., Towler, M. D., Littlewood, P. B.
We investigate the electronic, magnetic and orbital properties of La0.5Ca0.5MnO3 perovskite by means of an ab initio electronic structure calculation within the Hartree-Fock approximation. Using the...
The Diffusion Quantum Monte Carlo Method: Designing Trial Wave Functions for NiO (2001)
this paper we give a brief overview of the DMC method and describe its application to the transition metal monoxide NiO. Particular emphasis is placed on designing the approximate trial wave function...
Quantum Monte Carlo Simulations Of Real Solids (2001)
W. M. C. Foulkes, M. Nekovee, R. L. Gaudoin, M. L. Stedman, R. J. Needs, R. Q. Hood, ...
this article we'll concentrate on our QMC work since it's slightly easier to explain and particularly straightforward to implement on massively parallel computers. The generic term "quantum Monte...
Carbon clusters near the crossover to fullerene stability (1999)
Kent, P. R. C., Towler, M. D., Needs, R. J., Rajagopal, G.
The thermodynamic stability of structural isomers of $\mathrm{C}_{24}$, $\mathrm{C}_{26}$, $\mathrm{C}_{28}$ and $\mathrm{C}_{32}$, including fullerenes, is studied using density functional and...
Porter, A. R., Towler, M. D., Needs, R. J.
We report a first-principles theoretical study of hyperfine interactions, zero-point effects and defect energetics of muonium and hydrogen impurities in silicon and germanium. The spin-polarized...
Kent, P. R. C., Hood, Randolph Q., Towler, M. D., Needs, R. J., Rajagopal, G.
Quantum Monte Carlo (QMC) techniques are used to calculate the one-body density matrix and excitation energies for the valence electrons of bulk silicon. The one-body density matrix and energies are...
Quantum Monte Carlo Simulations Of Real Solids (1998)
W. M. C. Foulkes, M. Nekovee, R. L. Gaudoin, M. L. Stedman, R. J. Needs, R. Q. Hood, ...
this article we'll concentrate on our QMC work since it's slightly easier to explain and particularly straightforward to implement on massively parallel computers. The generic term "quantum Monte...
An Ab initio study of MnO and NiO (1994)
Towler, M D, Allan, N L, Harrison, N M, Saunders, V R, Mackrodt, W C, Apra, E
AB initio Hartree-Fock calculations of CaO, VO, MnO and NiO (1992)
Mackrodt, W C, Harrison, N M, Saunders, V R, Allan, N L, Towler, M D, Apra, E, ...
Quantum Monte Carlo Simulations Of Real Solids (1970)
W. M. C. Foulkes, M. Nekovee, R. L. Gaudoin, M. L. Stedman, R. J. Needs, R. Q. Hood, ...
this article we'll concentrate on our QMC work since it's slightly easier to explain and particularly straightforward to implement on massively parallel computers. The generic term "quantum Monte...