Subject: NBO/NRT and CpM systems

From: "Fred P. Arnold" <[email-masked]>
Date: Tue, 5 Jan 1999 21:39:42 -0600 (CST)

Hello,

When using NBO on transition metal systems with Cp, the standard routine
prints a structure with a mixture of single and 3-center bonds (C-C-M), at
least for early metals such as Ti.  When attempting to use the Natural
Resonance Theory section of the NBO program, how does one generate a
NRTLST entry (manual specification of reference structure), since the
3Cbond keyword is inoperable?  Should I pick one localized structure, say
a cyclopentadiene with two localized double bonds, and a lone pair on the
carbon not involved, pointing towards the metal, or is there a better way?
This question arises since the default routine is incapable of finding a
non-ionic structure on my system (CpL2TiR), and therefore NRT fails with a
thud, and without writing even the ionic structure as a starting point.

Thank you for your time.

							-fred

                                        Frederick P. Arnold, Jr.  
 "...But if you give theorists enough   Advanced Research Systems     
  time, they can predict anything."     5640 S. Ellis Ave             
        Dr. M. S. Turner, U. Chicago.   Chicago, IL 60637