"It is nice to know that the computer understands the problem, but I would
like to understand it too."
- Eugene Wigner |
The Natural Bond Orbital (NBO) program NBO 6.0
is a discovery tool for determining chemical bonding descriptors
of complex wavefunctions. NBO 6.0 is the current
implementation of the broad range
of 'natural' algorithms for optimally expressing numerical solutions of the
quantum mechanical Schrödinger equation in the chemically intuitive
language of Lewis-like bonding patterns and associated resonance-type
'donor-acceptor' interactions.
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Through their close association with elementary Lewis structure
diagrams, NBOs provide a direct link to familiar valency
and bonding concepts. Unlike delocalized MOs
(whose sprawling forms vary bewilderingly even between closely
related systems), NBOs are highly conserved
and transferable from one molecular environment
to another.
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NBOs are intrinsic realizations
of orbital-type bonding concepts
as originally envisioned by Pauling, Mulliken, and Coulson. Unlike methods based on derivatives
of charge density (a quasi-classical concept), NBO analysis exhibits
the unifying beauty of quantum phase-matching and
superposition principles
in all chemical phenomena.
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NBO provides mutually consistent and comprehensive
analysis tools, ensuring harmonious chemical
interpretations from one property to another. The program is
uniformly implemented in leading electronic
structure packages, providing an authoritative framework for
state-of-the-art professional discourse. Widespread acceptance
of the NBO paradigm is reflected in the burgeoning number
of published applications (currently, ~1500 per year).
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[Latest bugfix announcement:
October 13, 2014]
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August 24, 2015: Organometallics cover
"illustrates the dilemma created by applications of different
methods, here NBO and EDA-NOCV, for the extraction of bonding
information from ab initio computations - which method is better?
Because the analyses represent different interpretations,
rather than observables, there is no bottom-line criterion
for such a judgment. We are reminded of the complementary
contrariness of Tweedledee and Tweedledum in Lewis Carroll's
Through the Looking Glass and their inability to provide
Alice with directions on the best way out of the woods. The
cover was conceived by Russ Hughes, and the artwork was created
by Kate Nikles."
[C. R. Landis, R. P. Hughes, and F. Weinhold,
"Bonding Analysis of TM(cAAC)2 (TM = Cu, Ag, and Au) and the
Importance of Reference State,"
Organometall. 34, 3442-3449 (2015)]
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January 15, 2015:
In recognition of the 2nd anniversary of NBO 6.0 release,
the legacy NBO 5.9 program and website is being decommissioned
from active maintenance and support. Users requiring NBO 5.9
for compatibility with NBO6-incompatible or other older ESS versions
may still order through the legacy
NBO5 order form.
September 22, 2014:
C&E News cover story
"Pushing the Limits of Chemical Bonding" features NBO-based characterization of
anti-electrostatic H-bonding and other challenging cluster interactions.
June 1, 2014:
New ORCA v. 3.0.2 release now provides improved (correlated) densities
for NBO6-level analysis of DLPNO-CCSD(T) and other advanced methods
(more...)
May 14, 2014: Q-Chem, Inc.
announces release of Q-Chem v. 4.2 with NBO6 interface included
(more...)
October 1, 2013: The Frank Neese group of MPI-Mülheim
announces release of NBO6-compatible Orca v. 3.0
(more...)
August 16, 2013: Schrödinger Inc. announces release 2013-2 of
Jaguar v. 8.1, with NBO6 included
(more...)
July 28, 2013:
NBO6-level
NBOPro v.6 now available
(more...).
July 27, 2013:
Marcel Patek announces a set of utilities
to assist $NBO input preparation ("Gennbo Helper") and Jmol-based
orbital visualizations ("Jmol-NBO Visualization Helper")
in NBO-based applications. Companion videos
provide useful tutorial introduction to these utilities
(more...)
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May 8, 2013: J. Comp. Chem. cover feature:
"NBO 6.0, the next generation in natural bond orbital methods,...
includes link-free connectivity for
interfaces to popular electronic structure programs,
new methods of analysis, and numerous algorithmic
enhancements. The cover image is made with the NBOView 2.0
program and shows the sigma-type, 3-center/2-electron
bonding NBO of the cyclobutenyl cation that arises
from the strong overlap of the vacant valence orbital
at C1 with the C2-C3 bond. Automated multicenter bond
searches are one of the many new features of the NBO program."
[JCC 34, 1472 (2013)]
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May 6, 2013: NBO6-compatible
Gaussian 09 Rev. D.01 now available, with "pop=npa6",
"pop=nbo6read",
and related keywords
(more...)
April 11, 2013: NBO6-compatible Molpro v. 2012.1 now available
(more...)
April 8, 2013: SCM announces release of ADF2013, with NBO6 included
(more...)
March 12, 2013: "Early View" of J. Comp. Chem. article "NBO 6.0: Natural
Bond Orbital Analysis Program" (DOI: 10.1002/jcc.23266) now available
(more...)
February 4, 2013: NBO6 binaries for PC-Windows now available
(more...)
JANUARY 20, 2013: NBO6 ANNOUNCEMENT DAY
(more...)
December, 2012: GAMESS releases NBO6-compatible
source code version (more...)
NBO Home
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