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Avogadro with Gaussian + NBO
Avogadro with Gaussian + NBO
Published: 2015/05/06
Channel: IaNiusha
Comparing an MO with the Corresponding NBO Using WebMO
Comparing an MO with the Corresponding NBO Using WebMO
Published: 2016/04/10
Channel: John Keller
Visualizing Natural Bond Orbitals
Visualizing Natural Bond Orbitals
Published: 2013/03/05
Channel: ccclabmit
Multiple NBOS With GaussView and WebMO
Multiple NBOS With GaussView and WebMO
Published: 2016/04/12
Channel: John Keller
Discovering Chemistry With Natural Bond Orbitals
Discovering Chemistry With Natural Bond Orbitals
Published: 2016/10/15
Channel: Verbeke
03.05 Shapes of Natural Bond Orbitals
03.05 Shapes of Natural Bond Orbitals
Published: 2017/11/16
Channel: Michael Evans
Download Valency and Bonding A Natural Bond Orbital Donor Acceptor Perspective PDF
Download Valency and Bonding A Natural Bond Orbital Donor Acceptor Perspective PDF
Published: 2017/02/07
Channel: N. Octari
Chapter 1 – Electronic Structure and Bonding: Part 1 of 5
Chapter 1 – Electronic Structure and Bonding: Part 1 of 5
Published: 2015/08/29
Channel: Mike Christiansen
03.04 NBO Analysis of Methane
03.04 NBO Analysis of Methane
Published: 2017/11/16
Channel: Michael Evans
Will Synthetic Vitamins Make Me Explode?
Will Synthetic Vitamins Make Me Explode?
Published: 2015/06/30
Channel: Professor Dave Explains
03.03 Localized Molecular Orbitals and NBO Theory
03.03 Localized Molecular Orbitals and NBO Theory
Published: 2017/11/16
Channel: Michael Evans
The Tetrazine Ligation - Intrinsic Bond Orbitals
The Tetrazine Ligation - Intrinsic Bond Orbitals
Published: 2017/02/28
Channel: ClickChemist
Non-Conservativeness of Natural Orbital Systems by Slobodan Nedic
Non-Conservativeness of Natural Orbital Systems by Slobodan Nedic
Published: 2016/07/25
Channel: John Chappell
Orbitals, the Basics: Atomic Orbital Tutorial — probability, shapes, energy; Crash Chemistry Academy
Orbitals, the Basics: Atomic Orbital Tutorial — probability, shapes, energy; Crash Chemistry Academy
Published: 2017/09/23
Channel: ELLENT
Molecular Orbitals and Resonance
Molecular Orbitals and Resonance
Published: 2011/10/16
Channel: DukeOpenChemistry
[3,3]-Sigmatropic Rearrangements - Intrinsic Bond Orbitals
[3,3]-Sigmatropic Rearrangements - Intrinsic Bond Orbitals
Published: 2017/03/29
Channel: ClickChemist
Jmol-NBO Visualization Helper
Jmol-NBO Visualization Helper
Published: 2013/07/28
Channel: Org Med Chem
Frontier Molecular Orbital Theory (FMO Theory) & Gaussian |  | Part I
Frontier Molecular Orbital Theory (FMO Theory) & Gaussian | | Part I
Published: 2017/06/04
Channel: Transition State
Intrinsic Bond Orbital Analysis of a Strain-Promoted Alkyne Azide Cycloaddition
Intrinsic Bond Orbital Analysis of a Strain-Promoted Alkyne Azide Cycloaddition
Published: 2017/02/17
Channel: ClickChemist
Polymers - Crash Course Chemistry #45
Polymers - Crash Course Chemistry #45
Published: 2014/01/06
Channel: CrashCourse
NBO visualizer FAIL
NBO visualizer FAIL
Published: 2015/10/25
Channel: IaNiusha
sp3 hybridized orbitals and sigma bonds | Structure and bonding | Organic chemistry | Khan Academy
sp3 hybridized orbitals and sigma bonds | Structure and bonding | Organic chemistry | Khan Academy
Published: 2017/09/22
Channel: ELLENT
NBO analysis-organicchemistry Wagner College
NBO analysis-organicchemistry Wagner College
Published: 2014/11/19
Channel: Rob Craig
03.01 The Orbital Concept
03.01 The Orbital Concept
Published: 2017/11/14
Channel: Michael Evans
03.06 Polarization and Relative Energies
03.06 Polarization and Relative Energies
Published: 2017/11/16
Channel: Michael Evans
Localized Molecular Orbital Theory
Localized Molecular Orbital Theory
Published: 2012/06/05
Channel: Michael Evans
Orbital Calculation
Orbital Calculation
Published: 2014/01/11
Channel: ahmad fitri
Avogadro with Gaussian Tutorial MOs
Avogadro with Gaussian Tutorial MOs
Published: 2012/06/01
Channel: IaNiusha
OAT: Atomic and Molecular Structure Part 5 - Linear Combination of 1s Atomic Orbitals
OAT: Atomic and Molecular Structure Part 5 - Linear Combination of 1s Atomic Orbitals
Published: 2015/04/07
Channel: Master the Content
Jmol Viewer and display of NBOs in web browsers
Jmol Viewer and display of NBOs in web browsers
Published: 2012/11/18
Channel: Org Med Chem
Bond Order  (Quiz)
Bond Order (Quiz)
Published: 2012/08/14
Channel: Webcast-legacy Departmental
ADF Tutorial 11: Caffeine Bader (AIM) analysis, Benzene NBO visualization and Occupations
ADF Tutorial 11: Caffeine Bader (AIM) analysis, Benzene NBO visualization and Occupations
Published: 2015/12/10
Channel: AmsterdamDensityFunctional
KNIME UGM 2013 Bernd Wiswedel talk- Part 3 NBO
KNIME UGM 2013 Bernd Wiswedel talk- Part 3 NBO
Published: 2013/03/22
Channel: KNIMETV
NBO Income Calculator
NBO Income Calculator
Published: 2014/03/30
Channel: Uling Cyril
Análisis NBO con JmolNBO (NBO Analysis using JmolNBO)
Análisis NBO con JmolNBO (NBO Analysis using JmolNBO)
Published: 2016/08/26
Channel: UbEiDen Samboni
ETS-NOCV: Advanced chemical bonding analysis
ETS-NOCV: Advanced chemical bonding analysis
Published: 2014/03/03
Channel: AmsterdamDensityFunctional
Molecular Orbitals of Ethene
Molecular Orbitals of Ethene
Published: 2012/10/30
Channel: Jay Shore
Time evolution of the density, natural orbitals, and Sg
Time evolution of the density, natural orbitals, and Sg
Published: 2014/09/23
Channel: Quantum Cinema
Nuclear Chemistry: Crash Course Chemistry #38
Nuclear Chemistry: Crash Course Chemistry #38
Published: 2013/11/11
Channel: CrashCourse
Molecular orbital Meaning
Molecular orbital Meaning
Published: 2015/04/18
Channel: SDictionary
第19講 CH9 Covalent Bonding: Orbitals (B)
第19講 CH9 Covalent Bonding: Orbitals (B)
Published: 2013/01/12
Channel: NTHUOCW
Nbo Fast track system English version
Nbo Fast track system English version
Published: 2014/04/10
Channel: Uling Cyril
Lecture 15 - Chemical Reactivity: SOMO, HOMO, and LUMO
Lecture 15 - Chemical Reactivity: SOMO, HOMO, and LUMO
Published: 2011/10/16
Channel: Chang Barrick
The Evolution of Populations: Natural Selection, Genetic Drift, and Gene Flow
The Evolution of Populations: Natural Selection, Genetic Drift, and Gene Flow
Published: 2017/11/13
Channel: Professor Dave Explains
Gennbo Helper (first preview)
Gennbo Helper (first preview)
Published: 2013/07/21
Channel: Org Med Chem
TOP 21 Goals Have Natural Orbital Variables | QQ288 Malaysia
TOP 21 Goals Have Natural Orbital Variables | QQ288 Malaysia
Published: 2017/05/27
Channel: QQ Malaysia
Interpreting Gaussian Results
Interpreting Gaussian Results
Published: 2012/07/25
Channel: me0and0the0piano
Visualizing Orbitals
Visualizing Orbitals
Published: 2014/01/22
Channel: UofUChemistry
James Bond Theme (Moby
James Bond Theme (Moby's Re-Version) - Official video
Published: 2012/09/03
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Hybridization of Orbitals
Hybridization of Orbitals
Published: 2015/09/10
Channel: SliderBase
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WIKIPEDIA ARTICLE

From Wikipedia, the free encyclopedia
  (Redirected from Natural Bond Orbital)
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In quantum chemistry, a natural bond orbital or NBO is a calculated bonding orbital with maximum electron density. The NBOs are one of a sequence of natural localized orbital sets that include "natural atomic orbitals" (NAO), "natural hybrid orbitals" (NHO), "natural bonding orbitals" (NBO) and "natural (semi-)localized molecular orbitals" (NLMO). These natural localized sets are intermediate between basis atomic orbitals (AO) and molecular orbitals (MO):

Atomic orbital → NAO → NHO → NBO → NLMO → Molecular orbital

Natural (localized) orbitals are used in computational chemistry to calculate the distribution of electron density in atoms and in bonds between atoms. They have the "maximum-occupancy character" in localized 1-center and 2-center regions of the molecule. Natural bond orbitals (NBOs) include the highest possible percentage of the electron density, ideally close to 2.000, providing the most accurate possible “natural Lewis structure” of ψ. A high percentage of electron density (denoted %-ρL), often found to be >99% for common organic molecules, correspond with an accurate natural Lewis structure.

The concept of natural orbitals was first introduced by Per-Olov Löwdin in 1955, to describe the unique set of orthonormal 1-electron functions that are intrinsic to the N-electron wavefunction.[1]

Theory[edit]

Each bonding NBO σAB (the donor) can be written in terms of two directed valence hybrids (NHOs) hA, hB on atoms A and B, with corresponding polarization coefficients cA, cB:

σAB = cA hΑ + cB hB

The bonds vary smoothly from covalent (cA = cB) to ionic (cA >> cB) limit.

Each valence bonding NBO σ must be paired with a corresponding valence antibonding NBO σ* (the acceptor) to complete the span of the valence space:

σAB* = cA hΑcB hB

The bonding NBOs are of the "Lewis orbital"-type (occupation numbers near 2); antibonding NBOs are of the "non-Lewis orbital"-type (occupation numbers near 0). In an idealized Lewis structure, full Lewis orbitals (two electrons) are complemented by formally empty non-Lewis orbitals. Weak occupancies of the valence antibonds signal irreducible departures from an idealized localized Lewis structure, which means true "delocalization effects".[1]

Lewis structures[edit]

With a computer program that can calculate NBOs, optimal Lewis structures can be found. An optimal Lewis structure can be defined as that one with the maximum amount of electronic charge in Lewis orbitals (Lewis charge). A low amount of electronic charge in Lewis orbitals indicates strong effects of electron delocalization.

In resonance structures, major and minor contributing structures may exist. For amides, for example, NBO calculations show that the structure with a carbonyl double bond is the dominant Lewis structure. However, in NBO calculations, "covalent-ionic resonance" is not needed due to the inclusion of bond-polarity effects in the resonance structures.[2] This is similar to other modern valence bond theory methods.

See also[edit]

References[edit]

  1. ^ a b Weinhold, Frank; Landis, Clark R. (2001). "Natural Bond Orbitals and Extensions of Localized Bonding Concepts" (PDF). Chemistry Education Research and Practice. 2 (2): 91–104. doi:10.1039/B1RP90011K. 
  2. ^ Weinhold, Frank; Landis, Clark R. (2012). Discovering Chemistry With Natural Bond Orbitals. New Jersey: John Wiley & Sons. pp. 132–133. ISBN 978-1-118-22916-3. 

External links[edit]

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