ESS/NBO

See contact links (www.chem.wisc.edu/ nbo5/ess.htm) in Ref. 3c for NBO-affiliated electronic structure packages. 

Users of unlinked ESS hosts (including G09W users who wish to gain access to NB05-level options) may use a stand-alone version of NB05 (e.g., GENNBO 5.0W for PC-Windows users), but the process is a littie trickier. In this case, the ESS program must first be instructed to produce the NBO archive file for the calculated... 

No matter whether you are working with a linked or stand-alone NBO configurations, the manner of controlling NBO analysis through the keyword entries of the NBO keylist (the subject of this book) is the same for aU setups. Although different ESS hosts boast somewhat different capabilities, the implementation of NBO keylist commands is consistent across aU ESS platforms. We shall ignore further ESS-specific details as far as possible. 

Most orbital viewers are designed to import orbital data from the checkpoint file of the host ESS program or to directly read NBO PLOT (.31. 46) or ARCHIVE (.47) files. Communication with a chosen orhital viewer wfil therefore depend on details of its interface... 

NIC analysis requires a complex interactive partnership with a host ESS program that is capable of finite-field FC perturbation calculations, and is currently implemented only in NB05.9-linked versions of the Gaussian-09 program. Because separate FC perturbations are required for each coupled nucleus of interest, overall NIC analysis involves more Ga 55ia/J-specific job input detail than is required for other NBO keylist options (cf. Sidebar 7.1). For further details of NIC algorithms and input syntax, see the NBO Manual, p. B-147ff. 

Consult Section B. 2.4 of the NBO Manual for further details on restricting output (e.g., to valence shell or Lewis orbitals only), redirecting output to an external file, or checkpointing AO-based transformations (e.g., AONBO or AONLMO) to the host checkpoint file for CAS-type (Sidebar 11.2) or graphical (Appendix B) applications. The AOINFO keyword also provides additional detail (probably more than you wish to see) on orbital exponents and contraction coefficients of the Gaussian-type basis AOs that underlie the host ESS wavefunction calculation. 

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