Anion Electronic Anion Electronic Structure and Structure and Correlated, One-electron Correlated, One-electron Theory Theory J. V. Ortiz Department of Chemistry and Biochemistry Auburn University www.auburn.edu/cosam/JVOrtiz Workshop on Molecular Anions and Electron-Molecule Interactions in Honor of Professor Kenneth Jordan July 1, 2007 Park City, Utah
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Anion Electronic Structure and Correlated, One-electron Theory
Anion Electronic Structure and Correlated, One-electron Theory. J. V. Ortiz Department of Chemistry and Biochemistry Auburn University www.auburn.edu/cosam/JVOrtiz Workshop on Molecular Anions and Electron-Molecule Interactions in Honor of Professor Kenneth Jordan July 1, 2007 - PowerPoint PPT Presentation
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Anion Electronic Structure Anion Electronic Structure and Correlated, One-electron and Correlated, One-electron
TheoryTheoryJ. V. Ortiz
Department of Chemistry and Biochemistry
Auburn Universitywww.auburn.edu/cosam/JVOrtiz
Workshop on Molecular Anions and Electron-Molecule Interactions in Honor
of Professor Kenneth Jordan
July 1, 2007Park City, Utah
AcknowledgmentsAcknowledgmentsFunding National Science FoundationNational Science Foundation Defense Threat Reduction Defense Threat Reduction
AgencyAgency
Auburn CoworkersAuburn University• Department of Chemistry and Biochemistry
Symposium Organizers• Jack Simons• Brad Hoffman
UNAM Collaborators:• Ana Martínez• Alfredo Guevara
agenda:agenda: Deduce properties of Deduce properties of
molecules from quantum molecules from quantum mechanicsmechanics
Calculate chemical data, Calculate chemical data, especially if experiments especially if experiments are difficult or expensiveare difficult or expensive
Inductive agenda:Inductive agenda: Identify and explain Identify and explain
patterns in structure, patterns in structure, spectra, energetics, spectra, energetics, reactivityreactivity
Deepen and generalize the Deepen and generalize the principles of chemical principles of chemical bondingbonding
E. Schrödinger G. N. Lewis
Electron PropagatorTheory
Molecular OrbitalTheory Applications
Interpretation
Exactness
One-electron EquationsOne-electron Equations Hartree Fock TheoryHartree Fock Theory
Same potential for all i:Same potential for all i:core, valence, occupied, core, valence, occupied, virtual.virtual.
εεiiHFHF includes Coulomb and includes Coulomb and
exchange contributions to IEs exchange contributions to IEs and EAsand EAs
Electron Propagator Electron Propagator TheoryTheory
Dyson Equation:Dyson Equation:
[F + [F + ∑(∑(εεiiDysonDyson)])]φφii
DysonDyson = = εεiiDyson Dyson φφii
DysonDyson
Self energy, Self energy, ∑(E): ∑(E): Energy Energy dependent, nonlocal potential dependent, nonlocal potential that varies for each electron that varies for each electron binding energybinding energy
εεiiDysonDyson includes Coulomb, includes Coulomb,
exchange, relaxation and exchange, relaxation and correlation contributions to IEs correlation contributions to IEs and EAsand EAs
φφiiDysonDyson describes effect of electron describes effect of electron
detachment or attachment on detachment or attachment on electronic structureelectronic structure
Substituent Effects: U and TSubstituent Effects: U and T
Dyson Orbitals for U and T IEsDyson Orbitals for U and T IEs
Uracil
Thymine
π1 σ- π2 σ+ π3
Methyl (CH3) participation
Uracil Uracil versusversus Thymine Thymine
Methyl group destabilizes Methyl group destabilizes ππ orbitals orbitals with large with large amplitudes at nearest ring amplitudes at nearest ring atomatom
Therefore, IE(T) < IE(U)Therefore, IE(T) < IE(U) Valid principles for substituted DNA Valid principles for substituted DNA
bases, porphyrins and other organic bases, porphyrins and other organic moleculesmolecules
A Self-Energy for A Self-Energy for Large Molecules: P3Large Molecules: P3
Neglect off-diagonal elements of Neglect off-diagonal elements of ΣΣ(E) in (E) in canonical MO basis: canonical MO basis: φφii
DysonDyson(x) = P(x) = Pii½½ φφii
HF-CMOHF-CMO(x)(x) Partial summation of third-order diagramsPartial summation of third-order diagrams Arithmetic bottleneck: oNArithmetic bottleneck: oN44 (MP2 partial (MP2 partial
integral transformation)integral transformation) Storage bottleneck: oStorage bottleneck: o22vv22 in semidirect mode in semidirect mode Abelian, symmetry-adapted algorithm in G03Abelian, symmetry-adapted algorithm in G03
Nucleotides: phosphate-sugar-base DNA Nucleotides: phosphate-sugar-base DNA fragmentsfragments
Electrospray ion sourcesElectrospray ion sources Magnetic bottle detectionMagnetic bottle detection High resolution laser spectroscopy of ions, High resolution laser spectroscopy of ions,
mass spectrometrymass spectrometry Goal: predict photoelectron spectra of Goal: predict photoelectron spectra of
anionic nucleotides (vertical electron anionic nucleotides (vertical electron detachment energies or VEDEs)detachment energies or VEDEs)
Photoelectron Spectra of Photoelectron Spectra of 2’-deoxybase 5’-monophosphate 2’-deoxybase 5’-monophosphate
AnionsAnionsDAMP
DCMP
DGMP
DTMP
Base = adenine
Base = cytosine
Base = guanine
Base = thymine
L-S.Wang, 2004
Anomalous peak for dGMP
G: lowest IEof DNA bases
Dyson orbitals forlowest VEDEs:
phosphate or base?
DAMP Isomers and EnergiesDAMP Isomers and Energies
Phosphate anion reduces Base VEDEs Phosphate anion reduces Base VEDEs by several eVby several eV
Base also increases Phosphate VEDEsBase also increases Phosphate VEDEs Therefore, Base and Phosphate VEDEs Therefore, Base and Phosphate VEDEs
are closeare close Differential correlation effects are largeDifferential correlation effects are large Koopmans ordering is not reliableKoopmans ordering is not reliable
A Simple, Renormalized Self-A Simple, Renormalized Self-Energy: P3+Energy: P3+
Highly correlated motion Highly correlated motion of two diffuse (Rydberg) of two diffuse (Rydberg) electrons in the field of electrons in the field of a positive ion (NHa positive ion (NH44
+ + , , OHOH33
++)) United atom limit is an United atom limit is an
alkali anion: Naalkali anion: Na--
Extravalence atomic Extravalence atomic contributions in contributions in Dyson orbitalsDyson orbitals
NHNH44--
OHOH33--
Erx = -39.9
Eact = 5.1
IRC: CIRC: C3v3v OH OH33-- -> H -> H--(H(H22O)O)
X
x500
A
BC
Bowen’s Photoelectron Spectrum Bowen’s Photoelectron Spectrum of Nof N22HH77
Prediction and interpretation enable Prediction and interpretation enable dialogue with experimentalists dialogue with experimentalists requiring accurate datarequiring accurate data
Inductive, qualitative theory:Inductive, qualitative theory:Orbital formalism generalizes and Orbital formalism generalizes and deepens qualitative notions of deepens qualitative notions of electronic structure, relating structure, electronic structure, relating structure, spectra and reactivityspectra and reactivity