Quantum Chemistry July 5, 1995 Vol. 55, No. 1 Editorial ..................... 1 On the Definition of Nonadiabatic Effects in Curve-Crossing Problems J. BROECKHOVE, W. KEUTGENS, L. LATHOUWERS, AND P. VAN LEUVEN ...... 3 Calculation of Multicenter Electron Repulsion Integrals in Slater-Type Basis Sets Using the -Separation Method I. V. MASLOV, H. H. H. HOMEIER, AND E. O. STEINBORN ............... 9 Spin--Orbit Coupling in the Intersystem Crossing of the Ring- Opened Oxirane Biradical SOREN KNUTS, BORIS F. MINAEV, OLAV VAHTRAS AND HANS AGREN ......... 23 Theoretical Predictions of the Structures and Electronic Spectra of C_{60}NH^{+}_{2} with Comparisons with the Isoelectronic Molecules C_{60}O and C_{60}CH_{2} QIWEN TENG, JIKANG FENG, CHIACHUNG SUN, AND MICHAEL C. ZERNER ....... 35 PHGLF Calculations of Heliumlike Three-Body Systems YIXUAN WANG AND CONGHAO DENG ................. 47 Hybridization Displacement Charge in Molecules and Its Effects on Electrostatic Potentials and Fields ANIL KUMAR, C. G. MOHAN, AND P. C. MISHRA ................. 53 Conformational Structure of the Amphipathic Peptide Insecticide L-KALA FATEH S. NANDEL, ANUPAM AHLUWALIA, AND AMANDEEP KAUR ................. 61 A Comparative Study of Crystal Packing vs. Conformational Energy of N-Acetyl-2,3-Didehydroproline MIHIR ROYCHOUDHURY AND DEVESH KUMAR ................. 71 ============================================================= Quantum Chemistry July 15, 1995 Vol. 55, No. 2 Introduction ................. 75 The Historical Development of the Electron Correlation Problem PER-OLOV LOWDIN ................. 77 Local Quantum Chemistry: The Local Space Approximation for Moller--Plesset Perturbation Theory BERNARD KIRTMAN ................. 103 The Interaction of Chemical Bonds. IV. Interbond Charge Transfer by a Coupled-Cluster-Type Formalism PETER R. SURJAN ................. 109 Second-Order Intermediate Hamiltonian Method: Pilot Applications to Vertical Excitations in \pi-Electron Systems ANDREI ZAITSEVSKII AND JEAN-PAUL MALRIEU ................. 117 The Coupled-Cluster Method in High Sectors of the Fock Space S. R. HUGHES AND UZI KALDOR ................. 127 Coupled-Cluster Approaches with an Approximate Account of Triply and Quadruply Excited Clusters: Implementation of the Orthogonally Spin-Adapted CCD + ST(CCD), CCSD + T(CCSD), and ACPQ + ST(ACPQ) Formalisms PIOTR PIECUCH, ROBERT TOBOLA, AND JOSEF PALDUS ................. 133 A Formulation of Multiple-Reference CI with Terms Linear in the Interelectronic Distances. II. An Alternative Ansatz ROBERT J. GDANITZ AND ROBERT ROHSE ................. 147 Analytic Energy Derivatives for Coupled-Cluster Methods Describing Excited States: General Formulas and Comparison of Computational Costs PETER G. SZALAY ................. 151 On the Connections Between Brueckner--Coupled-Cluster, Density- Dependent Hartree--Fock, and Density Functional Theory GUSTAVO E. SCUSERIA ................. 165 Evaluating the Performance of Correlated Methods in Molecular Property Calculations: Pattern Recognition and Clustering in Spaces of Theoretical Descriptions GEORGE MAROULIS ................. 173 A Microscopic Coupled-Cluster Treatment of Electronic Correlations in Hubbard Models R. F. BISHOP, Y. XIAN, AND C. ZENG ................. 181 Spin-Adapted Restricted Hartree--Fock Reference Coupled-Cluster Theory for Open-Shell Systems: Noniterative Triples for Noncanonical Orbitals PAVEL NEOGRADY AND MIROSLAV URBAN ................. 187 Performance of Valence-Universal Multireference Coupled-Cluster Theory for Quasi-Degenerate States: The H8 and DZP H4 Models K. JANKOWSKI AND I. GRABOWSKI ................. 205 ============================================================= Quantum Chemistry Aug. 5, 1995 Vol. 55, No. 3 Ab Initio Calculations of Relativistic and Electron Correlation Effects in Polyatomics Using the Universal Gaussian Basis Set: XeF_{2} GULZARI L. MALLI, JACEK STYSZYNSKI, AND ALBERICO B. F. DA SILVA .... 213 Electron Correlation and Relativistic Effects in Xenon Tetrafluoride JACEK STYSZYNSKI AND GULZARI L. MALLI ................. 227 Nonadditive Interactions and the Relative Stability of Neutral and Anionic Silver Clusters I. G. KAPLAN, R. SANTAMARIA, AND O. NOVARO ................. 237 Effective Nonadiabatic Calculations On the Ground state of the HD^{+} Molecule PAWEL M. KOZLOWSKI AND LUDWIK ADAMOWICZ ................. 245 Ab Initio Conformational Study of the CO...H_{2} Van der Waals Dimer MARY C. SALAZAR, ALEXANDRA DE CASTRO, JOSE L. PAZ, GEERD H. F. DIERCKSEN AND ANTONIO J. HERNANDEZ ................. 251 Ab Initio Calculation of Stationary Points for the Ground and the First Excited State of HCO MARTINA BITTEREROVA, HANS LISCHKA, AND STANISLAV BISKUPIC .......... 261 Application of the Valence-Universal Coupled-Cluster Method Based on Various Model Spaces to ^{1}S States of Be K. JANKOWSKI AND P. MALINOWSKI ................. 269 Complete Active-Space Configuration Interaction with Optimized Orbitals: Application to Li_{2} STEFANO EVANGELISTI, GIAN LUIGI BENDAZZOLI, AND LAURA GAGLIARDI ..... 277 The QDPT CI Approach for Excitation and Ionization Spectra: A Test on the CO Molecule A. LISINI AND P. DECLEVA ................. 281 Electron Correlation Effects in Target Molecule in Low-Energy e^{-} + N_{2} Scattering SOURAV PAL, KEYA B. GHOSE, HANS-DIETER MEYER ................. 291 List of Participants ................. 299 ============================================================= Quantum Chemistry Vol. , No. Local-Scaling Transformation Version of Density Functional Theory EDUARDO V. LUDENA, ROBERTO LOPEZ-BOADA, JORGE E. MALDONADO, ELMER VALDERRAMA, EUGENE S. KRYACHKO, TOSHIKATSU KOGA, AND JUERGEN HINZE ................. 1 Coordinate Scaling and Adiabatic Connection Formula for Ensembles of Fractionally Occupied Excited States A. NAGY ................. 1 =============================================================