"The nature of the chemical bond is the problem at the heart of all chemistry."  -Bryce Crawford

At its core, the NBO program requires only minimal information from a host electronic structure system (ESS) program: the 1e density matrix (in unspecified AO basis) and the corresponding overlap matrix and angular symmetry labels (s,p,d,...) of the AOs. Neither the spatial forms of AOs (whether Gaussian-type, Slater-type, etc.) nor any other type of structural or energetic information is required for basic NAO/NBO/NLMO/NRT tasks.

However, many additional NBO analysis options (PLOT, 2nd-order energetic analysis, $DEL-deletions, NMR properties analysis, etc.) become available as additional information is provided from the ESS host. In many cases, the ESS/NBO information flow is passive and one-way (e.g., spatial information for PLOT output, or the converged Fock/Kohn-Sham matrix for energetic analysis, etc.), and non-interactive "stand-alone" GenNBO functionality suffices. However, more powerful ESS/NBO applications (such as $DEL-deletions or NEDA) require full two-way interactivity, which required binary linking in pre-NBO6 versions. That technical hurdle is removed in NBO7.

NBO7 is based on a message-passing protocol that allows free-standing ESS and NBO7 binaries to communicate and perform complex ESS/NBO7 "cooperative binary-pair" tasks. The NBO Team can provide the necessary snippets of template fortran freeware (and other technical assistance, as required) that allow your ESS program to begin interacting with an accessible NBO program.

The virtual ESS/NBO7 interface can be as simple or complex as you wish, depending on the message types you choose to implement (one- or two-way, services or requests for services, etc.). In principle, virtually any ESS can now implement the powerful $DEL-deletions, NEDA, NCS, and other interactive options that were previously accessible only in linked Gaussian/NBO5 or GAMESS/NBO5 configurations. In addition, many other types of NBO-based CAS/CC/CI methods and specialized property analyses can now be implemented to enhance (or show off) the unique capabilities of your ESS.

Contact Eric Glendening (eric.glendening@indstate.edu) for further information on building NBO7-compatibility into your ESS program.

The NBO 5.0 website and associated order form (for NBO5-level versions that link with older ESS versions) has been removed from service (October 2017).

Still older legacy code (such as the 1980s-vintage "NBO 3.1" included in current Gaussian distributions) is not supported by the NBO development team and is not considered to be of publishable reliability except for routine organic applications in modest basis sets. Users encountering difficulties with legacy NBO code should contact the help desk of the host ESS that provides such code.

News Archive FAQ Forum Featured apps NBO team contact us

Program & Distributor

ADF: Software for Chemistry & Materials N.V.
NOW AVAILABLE! ADF2017 with NBO6 included... (more)

DEMON2K: deMon Developers (demon-software.com)
[includes interface to write valid NBO archive (.47) files as input for stand-alone GenNBO programs (including that provided with NBO6)]

FIREFLY/PC-GAMESS: Alex Granovsky (Moscow State Univ.)
[includes NBO5 (requires TCI/NBO password); NBO6-compatible upgrade expected]

GAMESS(U.S.): Mark Gordon (Iowa State Univ.)
NOW AVAILABLE! NBO6-compatible source version offers fully interactive GAMESS/NBO6 functionality... <(more)>

GAUSSIAN: Gaussian, Inc.
NOW AVAILABLE! NBO6-compatible G16 offers full G09/NBO6 binary-to-binary interactivity... (more)

[Source G09, Rev. C can also be compiled and linked with source NBO6 (replacing "NBO 3.1" of the native distribution) for old-style G09/NBO6 linked interactivity... (more)]

JAGUAR: Schrödinger, Inc.
NOW AVAILABLE! NBO6 included in standard Jaguar 8.1 distribution... (more)

MOLCAS: Molcas.org (Univ. Lund)
[includes older NBO3-level code (NPA only)]

MOLPRO: H.-J. Werner (Univ. Stuttgart)
NOW AVAILABLE! NBO6-compatible Molpro v. 2012.1 allows source or binary level installation of NBO 6.0... (more)

NWCHEM: Pacific Northwest National Laboratories
[includes interface to NBO5; NBO6-compatible upgrade expected]

ORCA: Frank Neese (MPI-Mülheim)
NOW AVAILABLE! NBO6-compatible Orca v. 3.0 offers GenNBO6-type binary-to-binary functionality... (more)

PQS: Parallel Quantum Solutions
[includes NBO5; NBO6-compatible upgrade expected]

PSI4: PSI4 Project (Va. Tech., Ga. Tech.)
[includes interface to write valid NBO archive (.47) files as input for stand-alone GenNBO programs (including that provided with NBO6)]

Q-CHEM: Q-Chem, Inc.

NOW AVAILABLE! NBO6 interface (as well as installed NBO 5.0 program) now included in standard Q-Chem v. 5.0 distribution... ( more)

SPARTAN: Wavefunction, Inc.
[includes older NBO3-level code (NPA only)]

NOW AVAILABLE! NBO6 included in standard TeraChem distribution... ( User Guide, p. 16)

TURBOMOLE: Turbomole GmbH
[includes older NBO3-level code (NPA only)]

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