All Stories

  1. Thermochemical evaluation of adaptive and fixed density functional theory quadrature schemes

    Article • The Journal of Chemical Physics, December 2022, American Institute of Physics

    Peter Knowles

  2. Polaritonic effects in the vibronic spectrum of molecules in an optical cavity

    Article • The Journal of Chemical Physics, May 2022, American Institute of Physics

    Peter Knowles

  3. Perturbation-adapted perturbation theory

    Article • The Journal of Chemical Physics, January 2022, American Institute of Physics

    Peter Knowles

  4. Molecular second-quantized Hamiltonian: Electron correlation and non-adiabatic coupling treated on an equal footing

    Article • The Journal of Chemical Physics, September 2020, American Institute of Physics

    Peter Knowles

  5. The Molpro quantum chemistry package

    Article • The Journal of Chemical Physics, April 2020, American Institute of Physics

    Peter Knowles, David Kreplin, Kirk Peterson

  6. MCSCF optimization revisited. II. Combined first- and second-order orbital optimization for large molecules

    Article • The Journal of Chemical Physics, February 2020, American Institute of Physics

    David Kreplin, Peter Knowles

  7. Second-order MCSCF optimization revisited. I. Improved algorithms for fast and robust second-order CASSCF convergence

    Article • The Journal of Chemical Physics, May 2019, American Institute of Physics

    Peter Knowles, David Kreplin

  8. Direct quantum dynamics using variational Gaussian wavepackets and Gaussian process regression

    Article • The Journal of Chemical Physics, January 2019, American Institute of Physics

    Peter Knowles

  9. Rigorously extensive orbital-invariant renormalized perturbative triples corrections from quasi-variational coupled cluster theory

    Article • The Journal of Chemical Physics, February 2013, American Institute of Physics

    Peter Knowles

  10. Application of the quasi-variational coupled cluster method to the nonlinear optical properties of model hydrogen systems

    Article • The Journal of Chemical Physics, August 2012, American Institute of Physics

    Peter Knowles

  11. Benchmark Quasi-Variational Coupled Cluster Calculations of Multiple Bond Breaking

    Article • Journal of Chemical Theory and Computation, July 2012, American Chemical Society (ACS)

    Peter Knowles

  12. Quasi-variational coupled cluster theory

    Article • The Journal of Chemical Physics, February 2012, American Institute of Physics

    Peter Knowles

  13. Breaking multiple covalent bonds with Hartree–Fock-based quantum chemistry: Quasi-Variational Coupled Cluster theory with perturbative treatment of triple excitations

    Article • Physical Chemistry Chemical Physics, January 2012, Royal Society of Chemistry

    Peter Knowles

  14. Approximate variational coupled cluster theory

    Article • The Journal of Chemical Physics, July 2011, American Institute of Physics

    Peter Knowles

  15. Molpro: a general‐purpose quantum chemistry program package

    Article • Wiley Interdisciplinary Reviews Computational Molecular Science, July 2011, Wiley

    Peter Knowles

  16. Improved version of parallel programming interface for distributed data with multiple helper servers

    Article • Computer Physics Communications, July 2011, Elsevier

    Peter Knowles

  17. Benchmark studies of variational, unitary and extended coupled cluster methods

    Article • The Journal of Chemical Physics, December 2010, American Institute of Physics

    Peter Knowles

  18. A linked electron pair functional

    Article • The Journal of Chemical Physics, December 2010, American Institute of Physics

    Peter Knowles

  19. Hans-Joachim Werner

    Article • Molecular Physics, February 2010, Taylor & Francis

    Peter Knowles

  20. Parallel programming interface for distributed data

    Article • Computer Physics Communications, December 2009, Elsevier

    Peter Knowles

  21. High Accuracy ab Initio Calculations on Reactions of OH with 1-Alkenes. The Case of Propene

    Article • Journal of Chemical Theory and Computation, August 2009, American Chemical Society (ACS)

    Peter Knowles

  22. Theoretical rovibrational line intensities in the electronic ground state of ozone

    Article • Molecular Physics, November 2004, Taylor & Francis

    Peter Knowles

  23. Fast Hartree–Fock theory using local density fitting approximations

    Article • Molecular Physics, November 2004, Taylor & Francis

    Peter Knowles

  24. The CIPT2 method: Coupling of multi-reference configuration interaction and multi-reference perturbation theory. Application to the chromium dimer

    Article • Molecular Physics, November 2004, Taylor & Francis

    Peter Knowles

  25. Fast linear scaling second-order Møller-Plesset perturbation theory (MP2) using local and density fitting approximations

    Article • The Journal of Chemical Physics, April 2003, American Institute of Physics

    Peter Knowles

  26. Ab initio global potential, dipole, adiabatic, and relativistic correction surfaces for the HCN–HNC system

    Article • The Journal of Chemical Physics, August 2001, American Institute of Physics

    Peter Knowles, Jonathan Tennyson, Dr Attila Geza Csaszar

  27. Theoretical determination of the vibrational levels of NH+3and its isotopomers

    Article • Molecular Physics, August 2001, Taylor & Francis

    Peter Knowles

  28. Spin-orbit matrix elements for internally contracted multireference configuration interaction wavefunctions

    Article • Molecular Physics, November 2000, Taylor & Francis

    Peter Knowles

  29. The ion-molecule reaction O+(4S) + N2(X1Σ+) → NO+(X1Σ+,v′) + N(4S) and the predissociation of the A2Σ+and B2Π sta...

    Article • Molecular Physics, November 2000, Taylor & Francis

    Peter Knowles

  30. Theoretical photoabsorption spectra of Arn+ clusters

    Article • Chemical Physics Letters, August 2000, Elsevier

    Peter Knowles

  31. Convergence of Breit–Pauli spin–orbit matrix elements with basis set size and configuration interaction space: The halogen atoms F, Cl, and Br

    Article • The Journal of Chemical Physics, April 2000, American Institute of Physics

    Peter Knowles

  32. Erratum: “Coupled cluster theory for high spin, open shell reference wave functions” [ J. Chem. Phys. 99, 5219 (1993)]

    Article • The Journal of Chemical Physics, February 2000, American Institute of Physics

    Peter Knowles

  33. Spectroscopic and theoretical characterization of linear centrosymmetric N≡N⋅⋅H+⋅⋅N≡N

    Article • The Journal of Chemical Physics, November 1999, American Institute of Physics

    Peter Knowles

  34. Induced dipole—induced dipole interactions in Ar+nclusters

    Article • Molecular Physics, March 1999, Taylor & Francis

    Peter Knowles

  35. Theoretical photoabsorption spectrum of Ar3+

    Article • Chemical Physics Letters, February 1999, Elsevier

    Peter Knowles

  36. Accurate Configuration Interaction Computations of Potential Energy Surfaces using Massively Parallel Computers

    Article • January 1999, Springer Science + Business Media

    Peter Knowles

  37. Accurate diatomics-in-molecules calculations on Ar+n clusters

    Article • Molecular Physics, August 1998, Taylor & Francis

    Peter Knowles

  38. A comparative study of methods for describing non-adiabatic coupling: diabatic representation of the 1Σ+/1Π HOH and HHO conical intersections

    Article • Molecular Physics, August 1997, Taylor & Francis

    Peter Knowles

  39. A comparative study of methods for describing non-adiabatic coupling: diabatic representation of the 1Sigma +/1Pi HOH and HHO conical intersections

    Article • Molecular Physics, August 1997, Taylor & Francis

    Peter Knowles

  40. Accurate numerical determination of Kohn-Sham potentials from electronic densities: I. Two-electron systems

    Article • The Journal of Chemical Physics, June 1997, American Institute of Physics

    Peter Knowles

  41. Erratum to “Generation of functional derivatives in Kohn-Sham density-functional theory” [Comput. Phys. Commun. 100 (1997) 93–98]

    Article • Computer Physics Communications, June 1997, Elsevier

    Peter Knowles

  42. Generation of functional derivatives in Kohn-Sham density-functional theory

    Article • Computer Physics Communications, February 1997, Elsevier

    Peter Knowles

  43. Theoretical determination of the heat of formation of methylene

    Article • Journal of the Chemical Society Faraday Transactions, January 1997, Royal Society of Chemistry

    Peter Knowles

  44. Potential energy surfaces from Kohn-Sham potentials

    Article • Chemical Physics Letters, November 1996, Elsevier

    Peter Knowles

  45. Improved radial grids for quadrature in molecular density-functional calculations

    Article • The Journal of Chemical Physics, June 1996, American Institute of Physics

    Peter Knowles

  46. The structures and stabilities of helium cluster ions

    Article • Molecular Physics, March 1996, Taylor & Francis

    Peter Knowles

  47. The metastable quartet state of He+4

    Article • The Journal of Chemical Physics, June 1995, American Institute of Physics

    Peter Knowles

  48. Ann-valued representation of He+npotentials

    Article • Molecular Physics, June 1995, Taylor & Francis

    Peter Knowles

  49. Exchange energy in Kohn-Sham density-functional theory

    Article • Physical Review A, May 1995, American Physical Society (APS)

    Peter Knowles

  50. Microwave electronic spectrum of the He+2 ion

    Article • The Journal of Chemical Physics, April 1995, American Institute of Physics

    Peter Knowles

  51. Perturbative corrections to account for triple excitations in closed and open shell coupled cluster theories

    Article • Chemical Physics Letters, September 1994, Elsevier

    Peter Knowles

  52. Coupled cluster theory for high spin, open shell reference wave functions

    Article • The Journal of Chemical Physics, October 1993, American Institute of Physics

    Peter Knowles

  53. Theoretical spin–rovibronic 2A1(Πu)–2B1 spectrum of the H2O+, HDO+, and D2O+ cations

    Article • The Journal of Chemical Physics, April 1993, American Institute of Physics

    Peter Knowles

  54. Internally contracted multiconfiguration-reference configuration interaction calculations for excited states

    Article • October 1992, Springer Science + Business Media

    Peter Knowles

  55. Restricted Møller—Plesset theory for open-shell molecules

    Article • Chemical Physics Letters, November 1991, Elsevier

    Peter Knowles

  56. A full-CI study of the energetics of the reaction F + H2 → HF+H

    Article • Chemical Physics Letters, October 1991, Elsevier

    Peter Knowles

  57. Open-shell M∅ller—Plesset perturbation theory

    Article • Chemical Physics Letters, October 1991, Elsevier

    Peter Knowles

  58. A b i n i t i o calculations on the four lowest electronic states of AlF+ and AlCl+

    Article • The Journal of Chemical Physics, October 1991, American Institute of Physics

    Peter Knowles

  59. ChemInform Abstract: Theoretical Assignment of the Visible Spectrum of Singlet Methylene

    Article • ChemInform, April 1991, Wiley

    Peter Knowles

  60. Ab initio characterization of NF2+

    Article • Journal of Physics B Atomic Molecular and Optical Physics, April 1991, Institute of Physics Publishing

    Peter Knowles

  61. The 3.PI.8 .rarw. 3.SIGMA.u+ transition in nitrogen (N22+)

    Article • The Journal of Physical Chemistry, March 1991, American Chemical Society (ACS)

    Peter Knowles

  62. Accurate multireference configuration interaction calculations of the potential energy function and the dissociation energy of N2

    Article • The Journal of Chemical Physics, January 1991, American Institute of Physics

    Peter Knowles

  63. A comparison of variational and non-variational internally contracted multiconfiguration-reference configuration interaction calculations

    Article • January 1991, Springer Science + Business Media

    Peter Knowles

  64. Theoretical assignment of the visible spectrum of singlet methylene

    Article • The Journal of Chemical Physics, January 1991, American Institute of Physics

    Peter Knowles

  65. Low-lying electronic states of PH2+

    Article • Chemical Physics Letters, December 1990, Elsevier

    Peter Knowles

  66. Theoretical radiative transition probabilities of the CS+ ion

    Article • Chemical Physics, October 1990, Elsevier

    Peter Knowles

  67. Multireference—configuration interaction (MRCI) calculations of HS2+ and experimental observation via electron impact ionization of H2S

    Article • International Journal of Mass Spectrometry and Ion Processes, October 1990, Elsevier

    Peter Knowles

  68. A b i n i t i o study of the energetics of the spin-allowed and spin-forbidden decomposi...

    Article • The Journal of Chemical Physics, September 1990, American Institute of Physics

    Peter Knowles

  69. A b i n i t i o calculation of the X 2Σ+ and A 2Π states of CF++

    Article • The Journal of Chemical Physics, July 1990, American Institute of Physics

    Peter Knowles

  70. A theoretical rotationally resolved infrared spectrum for H2O+ (X 2B1)

    Article • The Journal of Chemical Physics, September 1989, American Institute of Physics

    Peter Knowles

  71. Unlimited full configuration interaction calculations

    Article • The Journal of Chemical Physics, August 1989, American Institute of Physics

    Peter Knowles

  72. A determinant based full configuration interaction program

    Article • Computer Physics Communications, April 1989, Elsevier

    Peter Knowles

  73. Very large full configuration interaction calculations

    Article • Chemical Physics Letters, March 1989, Elsevier

    Peter Knowles

  74. The A 2Π–X 2Σ+ red and B 2Σ+–X 2Σ+ violet systems of the CN radical: Accurate multireference configuration interaction calculations of the radiative transition probabilities

    Article • The Journal of Chemical Physics, December 1988, American Institute of Physics

    Peter Knowles

  75. An efficient internally contracted multiconfiguration–reference configuration interaction method

    Article • The Journal of Chemical Physics, November 1988, American Institute of Physics

    Peter Knowles

  76. Projected unrestricted Mo/ller–Plesset second-order energies

    Article • The Journal of Chemical Physics, June 1988, American Institute of Physics

    Peter Knowles

  77. Convergence of projected unrestricted Hartee-Fock Moeller-Plesset series.

    Article • The Journal of Physical Chemistry, June 1988, American Chemical Society (ACS)

    Peter Knowles

  78. On the assignment of the electronically excited singlet states in linear CO2

    Article • Chemical Physics Letters, May 1988, Elsevier

    Peter Knowles

  79. An efficient method for the evaluation of coupling coefficients in configuration interaction calculations

    Article • Chemical Physics Letters, April 1988, Elsevier

    Peter Knowles

  80. Slow convergence of the møller-plesset perturbation series: the dissociation energy of hydrogen cyanide and the electron affinity of the cyano radical

    Article • Chemical Physics Letters, July 1987, Elsevier

    Peter Knowles

  81. On the validity and applicability of the connected moments expansion

    Article • Chemical Physics Letters, March 1987, Elsevier

    Peter Knowles

  82. An MCSCF study of the X 2 B 2, 2 A 2 and 2 2 B 2 states of benzyl

    Article • Journal of the Chemical Society Faraday Transactions 2 Molecular and Chemical Physics, January 1987, Royal Society of Chemistry

    Peter Knowles

  83. Non-expanded dispersion and induction energies, and damping functions, for molecular interactions with application to HF-He

    Article • Molecular Physics, December 1986, Taylor & Francis

    Peter Knowles

  84. Benchmark full configuration-interaction calculations on HF and NH2

    Article • The Journal of Chemical Physics, August 1986, American Institute of Physics

    Peter Knowles

  85. Non-expanded dispersion energies and damping functions for Ar2 and Li2

    Article • Chemical Physics Letters, February 1986, Elsevier

    Peter Knowles

  86. On the convergence of the M�ller-Plesset perturbation series

    Article • July 1985, Springer Science + Business Media

    Peter Knowles

  87. A second order multiconfiguration SCF procedure with optimum convergence

    Article • The Journal of Chemical Physics, June 1985, American Institute of Physics

    Peter Knowles

  88. AB-initio prediction of properties of carbon dioxide, ammonia, and carbon dioxide...ammonia

    Article • The Journal of Physical Chemistry, May 1985, American Chemical Society (ACS)

    Peter Knowles

  89. An efficient second-order MC SCF method for long configuration expansions

    Article • Chemical Physics Letters, April 1985, Elsevier

    Peter Knowles

  90. The calculation of higher-order energies in the many-body perturbation theory series

    Article • Chemical Physics Letters, January 1985, Elsevier

    Peter Knowles

  91. A new determinant-based full configuration interaction method

    Article • Chemical Physics Letters, November 1984, Elsevier

    Peter Knowles

  92. An accurate variational wave function for lithium hydride

    Article • The Journal of Physical Chemistry, October 1984, American Chemical Society (ACS)

    Peter Knowles

  93. Analytic energy second derivatives for general MCSCF wave functions

    Article • The Journal of Chemical Physics, March 1984, American Institute of Physics

    Peter Knowles

  94. A potential energy surface for the ground state of CH2

    Article • Molecular Physics, June 1983, Taylor & Francis

    Peter Knowles

  95. Studies using the CASSCF wavefunction

    Article • Chemical Physics, November 1982, Elsevier

    Peter Knowles

  96. Selective reduction of organic compounds with bis-(η-cyclopentadienyl)dihydridotungsten

    Article • Journal of the Chemical Society Perkin Transactions 1, January 1973, Royal Society of Chemistry

    Peter Knowles