Analytic non-adiabatic couplings for the spin-flip ORMAS method

2020 ◽  
Vol 22 (3) ◽  
pp. 1475-1484 ◽  
Author(s):  
Joani Mato ◽  
Mark S. Gordon
Keyword(s):  
Configuration Interaction ◽  
Matrix Elements ◽  
Coupling Matrix ◽  
Active Space ◽  
Spin Flip

Analytic non-adiabatic coupling matrix elements (NACME) are derived and implemented for the spin-flip occupation restricted multiple active space configuration interaction (SF-ORMAS-CI) method.

Restricted active space spin-flip configuration interaction: Theory and examples for multiple spin flips with odd numbers of electrons

2012 ◽  
Vol 137 (16) ◽  
pp. 164110 ◽  
Author(s):  
Paul M. Zimmerman ◽  
Franziska Bell ◽  
Matthew Goldey ◽  
Alexis T. Bell ◽  
Martin Head-Gordon
Keyword(s):  
Configuration Interaction ◽  
Interaction Theory ◽  
Active Space ◽  
Spin Flip ◽  
Spin Flips

Convergence of Breit–Pauli spin–orbit matrix elements with basis set size and configuration interaction space: The halogen atoms F, Cl, and Br

2000 ◽  
Vol 112 (13) ◽  
pp. 5624-5632 ◽  
Author(s):  
Andreas Nicklass ◽  
Kirk A. Peterson ◽  
Andreas Berning ◽  
Hans-Joachim Werner ◽  
Peter J. Knowles
Keyword(s):  
Configuration Interaction ◽  
Interaction Space ◽  
Basis Set ◽  
Spin Orbit ◽  
Matrix Elements ◽  
Set Size ◽  
Halogen Atoms

Superconducting Pairs in Clusters and in the Cu-O Plane

1999 ◽  
Vol 13 (09n10) ◽  
pp. 1195-1200
Author(s):  
Michele Cini ◽  
Adalberto Balzarotti ◽  
Gianluca Stefanucci
Keyword(s):  
Configuration Interaction ◽  
Interaction Mechanism ◽  
Second Order ◽  
Flux Quantization ◽  
Spin Flip ◽  
Full Plane ◽  
Superconducting Pairing ◽  
Exact Diagonalisation

Recently, by exact diagonalisation methods, we reported superconducting pairing and flux quantization in Cu-O Hubbard clusters of up to 21 atoms. The pairing is due to a configuration interaction mechanism driven by symmetry, and arises when the least bound holes have vanishing mutual repulsion ( W =0 pairs). The second-order, spin-flip interaction leads to a net attraction for the singlet and repulsion for the triplet. Here we show that electron bound pairs also exist and show similar flux quantization properties. Then, we extend the theory of pairing to the full plane and to all orders.

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