LocalSCF

LocalSCF is a variational linear scaling quantum-mechanical (QM) method implemented at present in the semi-empirical framework. It is designed for the fast electronic structure calculations of large, complex biomolecules. The program utilizes the standard neglect of differential diatomic overlap (NDDO) approach and supports the MNDO, AM1, PM3, and PM5 semi-empirical Hamiltonians. All chemical elements are treated in the sp-basis set with the exception of transition metals where additional consideration of d-orbitals is included. The program performs closed-shell RHF energy calculations and geometry optimizations in gas phase and can incorporate solvent effects using the COSMO continuum solvent model. Fast Multipole Method (FMM) is implemented to handle long-range Coulomb interactions in linear scaling fashion. Born-Oppenheimer and Langevin dynamics are supported. Temperature control is performed via Berendsen and Nose-Hoover thermostats. Integration of dynamics equation is performed by using BBK algorithm, Nose-Hoover update scheme, and Leapfrog Verlet integrator.