v1.7.1

• New Features
  • SCF and analytical gradients for the PM6 semi-empirical method
  • Density matrix purification methods for PM6
  • Analytic gradient and NACV for spin-flip TDDFT/TDA
  • qmmm.pbc for UKS
• Improvements
  • Accelerated vv10 energy calculation (#751)
  • Optimized vv10 grid response gradient performance (#749)
  • Optimized XC gradient performance with grid response (#755)
  • Applied sparsity to XC Hessian (#766)
  • GPU-accelerated vppnl_nuc_grad for GTH pseudopotentials (#740)
  • SCF initial guess to include MO coefficients to accelerate the first Fock build
• Fixes
  • SG1 grid radius for ghost atoms
  • Convergence threshold checks in the UCDFT second-order solver