From owner-chemistry@ccl.net Thu Jan  3 00:14:00 2019
From: "Kavitha Velappan kavitha.velappan-*-gmail.com" <owner-chemistry a server.ccl.net>
To: CCL
Subject: CCL:G: Occupancy in NBO analysis
Message-Id: <-53579-190103000940-8610-NAG2vceZH+4k+LSydivX4g a server.ccl.net>
X-Original-From: "Kavitha  Velappan" <kavitha.velappan..gmail.com>
Date: Thu, 3 Jan 2019 00:09:39 -0500


Sent to CCL by: "Kavitha  Velappan" [kavitha.velappan : gmail.com]
Dear CCL users,

I optimized the geometry of a molecule in Gaussian 16W using DFT(B3LYP)/6-
311++G(2d,p) basis set. The optimized geometry was used as input for NBO 
analysis implemented in Gaussian 16W. I observed that the occupancy is less 
than 1 for even core orbitals. But what I understood from NBO manual is the 
occupancy will be between 0 and 2. If so why I am getting occupancy less 
than 1 for my molecule? Is it an indication that the input geometry is not 
correct? What does it imply? 
Any suggestion would be appreciated.
Kavitha