From owner-chemistry@ccl.net Sun Apr 15 05:01:01 2018 From: "Grigoriy Zhurko reg_zhurko..chemcraftprog.com" To: CCL Subject: CCL: Choice of multiplicity for NiO Message-Id: <-53236-180415045332-7086-Hwtzp9arFQVv2fPgmL5xAw__server.ccl.net> X-Original-From: Grigoriy Zhurko Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=us-ascii Date: Sun, 15 Apr 2018 11:54:08 +0400 MIME-Version: 1.0 Sent to CCL by: Grigoriy Zhurko [reg_zhurko%a%chemcraftprog.com] Hello, I compute Ni4O4, Ni9O4 clusters and their complexes with carbon monoxide (me research is devoted to CO absorption on NiO). These systems can be computed in different multiplicities. Two approaches can be used for choosing the multiplicities: 1) Compute each multiplicity and find the one with minimal energy; 2) In the work of Thomas Bredow, only the multiplicity 19 was chosen for Ni9O9. He writes in his paper: The Ni9O9 cluster was calculated with a multiplicity of 19. This corresponds to a ferromagnetic state of NiO where each nickel is formally Ni2+ with a 3B2 ground state (local C4V symmetry). The ground state of solid NiO is antiferromagnetic AF2 with parallel spins along the (111) planes,21 but the energetic difference between the ferromagnetic and the antiferromagnetic state is within a few kJ/mol, and it is assumed that magnetic coupling between the Ni atoms does not play an important role in the CO adsorption process. What approach is better? If the approach of Thomas Bredow is more appropriate, what multiplicity should be chosen as the only one for Ni4O4 molecules and their complexes with CO? I suppose, this should be the 9 multiplicity. Grigoriy Zhurko https://chemcraftprog.com/