Views
3 years ago

Experimental, Hartree-Fock, and Density Functional Theory ...

Experimental, Hartree-Fock, and Density Functional Theory ...

Experimental, Hartree-Fock, and Density Functional Theory

4708 J. Am. Chem. Soc. 2000, 122, 4708-4717Experimental, Hartree-Fock, and Density Functional TheoryInvestigations of the Charge Density, Dipole Moment, ElectrostaticPotential, and Electric Field Gradients in L-Asparagine MonohydrateWilliam D. Arnold, † Lori K. Sanders, † Michael T. McMahon, † Anatoliy V. Volkov, ‡Guang Wu, ‡ Philip Coppens, ‡ Scott R. Wilson, † Nathalie Godbout, † and Eric Oldfield* ,†Contribution from the Department of Chemistry, UniVersity of Illinois at Urbana-Champaign,600 South Mathews AVenue, Urbana, Illinois 61801, and Chemistry Department,State UniVersity of New York at Buffalo, Buffalo, New York 14260-3000ReceiVed February 1, 2000Abstract: We have investigated the charge density, F(r), its curvature, ∂ 2 F/∂r ij , the dipole moment, µ, and theelectrostatic potential, Φ(r), in L-asparagine monohydrate by using high-resolution single-crystal X-raycrystallography and quantum chemistry. In addition, we have compared electric field gradient, ∇E, resultsobtained from crystallography and quantum chemistry with those obtained from single-crystal 14 N nuclearmagnetic resonance spectroscopy. A multipole model of the X-ray F(r) is compared to Hartree-Fock anddensity functional theory predictions, using two different large basis sets. The quality of the calculated chargedensities is evaluated from a simultaneous comparison of eight Hessian-of-F(r) tensors at bond critical pointsbetween non-hydrogen atoms. These tensors are expressed in an icosahedral representation, which includesinformation on both tensor magnitude and orientation. The best theory-versus-experiment correlation is foundat the B3LYP/6-311++G(2d,2p) level, which yields a slope of 1.09 and an R 2 value of 0.96. Both DFT andHF results give molecular dipole moments in good accord with the value extracted from the X-ray diffractiondata, 14.3(3) D, and both sets of calculations are found to correctly reproduce the experimental molecularelectrostatic potential, Φ(r). The intermolecular hydrogen bond F(r) is also subjected to a detailed theoreticaland experimental topological analysis, and again good agreement is found between theory and experiment.For the comparison of the ∇E tensors, the icosahedral representation is again used. There is found to bemoderate accord between theory and experiment when using results obtained from diffraction data, but muchbetter accord when using results obtained from NMR data (slope ) 1.14, R 2 ) 0.94, for the 12 icosahedraltensor elements for N1 and N2). Overall, these results strongly support the idea that both HF and DFT methodsgive excellent representations of the electrostatic properties F(r), ∂ 2 F/∂r ij , µ, Φ(r), and ∇E, for crystallineL-asparagine monohydrate, encouraging their future use in situations where experimental results are lacking,such as in peptides and in enzyme active sites.IntroductionThere is currently considerable interest in using quantumchemical methods to investigate structure and bonding inmolecules of ever increasing size and to help predict and refinethe structures of molecules using spectroscopic observables. 1In our group at the University of Illinois, we have been usingquantum chemical methods to help interpret both isotropicchemical shifts and chemical shift tensors in proteins and modelsystems, to provide new approaches to protein structurerefinement. 1-4 In the case of 13 C R , 13 C β , and 13 C γ shiftdeterminations, we have generally used Hartree-Fock (HF)methods, 5,6 while in the case of metalloporphyrins, we have used† University of Illinois.‡ State University of New York.(1) Oldfield, E. J. Biomol. NMR 1995, 5, 217-225.(2) deDios, A. C.; Pearson, J. G.; Oldfield, E. Science 1993, 260, 1491-1496.(3) Pearson, J. G.; Wang, J.; Markley, J. L.; Le, H.; Oldfield, E. J. Am.Chem. Soc. 1995, 117, 8823-8829.(4) McMahon, M. T.; deDios, A. C.; Godbout, N.; Salzmann, R.; Laws,D. D.; Le, H.; Havlin, R. H.; Oldfield, E. J. Am. Chem. Soc. 1998, 120,4784-4797.(5) Havlin, R. H.; Le, H.; Laws, D. D.; deDios, A. C.; Oldfield, E. J.Am. Chem. Soc. 1997, 119, 11951-19958.density functional theory (DFT) methods with hybrid functionalsto investigate both metal and ligand shieldings, 7-10 since thesegive the best agreement between theory and experiment. And,as a bonus from the SCF part of these calculations, we haveaccess to a large base of electrostatic properties which can bederived at little extra computational cost. The general questionthen arises: How accurate might these computed electrostaticproperties, such as the charge density, F(r), its curvature, ∂ 2 F/∂r ij , the dipole moment, µ, the electrostatic potential, Φ(r), andthe electric field gradient, ∇E, be?We report here high-resolution single-crystal X-ray diffractiondata (obtained by using synchrotron radiation with an areadetector) on L-asparagine‚H 2 O, which contains a hydrogenbondedamide group, and we investigate the F(r), ∂ 2 F/∂r ij , µ,Φ(r), and ∇E values determined both experimentally (from(6) Pearson, J. G.; Le, H.; Sanders, L. K.; Godbout, N.; Havlin, R. H.;Oldfield, E. J. Am. Chem. Soc. 1997, 119, 11941-11950.(7) Salzmann, R.; Kaupp, M.; McMahon, M.; Oldfield, E. J. Am. Chem.Soc. 1998, 120, 4771-4783.(8) Godbout, N.; Oldfield, E. J. Am. Chem. Soc. 1997, 119, 8065-8069.(9) Havlin, R. H.; McMahon, M.; Srinivasan, R.; Le, H.; Oldfield, E. J.Phys. Chem. 1997, 101, 8908-8913.(10) Godbout, N.; Havlin, R.; Salzmann, R.; Wojdelski, M.; Debrunner,P. G.; Oldfield, E. J. Phys. Chem. 1998, 102, 2342-2350.10.1021/ja000386d CCC: $19.00 © 2000 American Chemical SocietyPublished on Web 04/27/2000

Brueckner-Hartree-Fock EOS for stellar structure - Infn
Local Density Functional Theory for Superfluid Fermionic Systems ...
Reduced Density-Matrix Functional Theory in OCTOPUS - TDDFT.org
Local Density Functional Theory for Superfluid Fermionic Systems ...
New density functionals by Yan Zhao - Chemical Theory Center ...
Time-dependent density functional theory for non-linear phenomena ...
Teoría del Funcional de la Densidad (Density Functional Theory)
Introduction to DFT and density functionals - PiTP
Combining Theory, Modeling and Experimentation to Understand ...
Microscopic level densities, Strength functions, & TALYS - efnudat
Probability density of wave function of excited photoelectron
Elementary Analytic Functions - Complex Functions Theory a-1
Structural functionalism Conflict theory Symbolic Interactionism ...
Calculus of Residua - Complex Functions Theory a-2
Density function of spot returns conditional to both total ... - RiskLab
Recent development of the theory of matrix monotone functions and ...
towards a unified theory of saccadic function - Laboratory of Visual ...
Audiobook Acupuncture, Meridian Theory and Acupuncture Points Li Ding ForIpad
hartree–fock (hf) method and density functional theory calculations
Resolution-of-identity approach to Hartree–Fock, hybrid density ...
Symmetry Restoration in Hartree-Fock-Bogoliubov Based Theories
An Introduction to Hartree-Fock Molecular Orbital Theory
Application of the gradient method to Hartree-Fock-Bogoliubov theory
minimizers for the hartree-fock-bogoliubov theory of neutron stars ...