Boundary Adjustments (i)Selective deletion of 1e integrals

• L1: Delete integrals for which basis functions i or j are sited on the link atom L
  • found to be effective for semi-empirical wavefunctions
  • difference in potential acting on nearby basis functions causes unphysical polarisation for ab-initio QM models
  use coupling=L1 with qm_theory=mndo
• L3: Delete integrals for which basis functions i and j are cited on the link atom and qA is the neighbouring MM atom (M1)
  • less consistent results observed in practice †

† Classification from Antes and Thiel, in Combined Quantum Mechanical and Molecular Mechanical Methods, J. Gao and M. Thompson, eds. ACS Symp. Ser., Washington DC, 1998.

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