Subject: NBO problem with LPs

From: Jesús Rodríguez Otero <[email-masked]>
Date: Fri, 5 Oct 2001 13:21:15 +0200

Hi

I have a serious problem with NBO calculations with the two LPs of the oxigen atoms.
For instance, with the water molecule (HF, DFT or MP2) the two lone pairs of the oxigen atoms adopt a very singular arrangement:
one LP in the molecular plane (a hybrid aprox sp), an the other LP being a pure p orbital, absolutely perpendicular to the plane.
This is totally different to the expected: two LPs with sp3 character, above and below the plane.
Do NBO calculations work well???
Anybody has a similar problem??

Thanks in advance

Jesus Rodriguez Otero
[email-masked]