Systematic generation of finite-range atomic basis sets for   linear-scaling calculations
  Basis sets of atomic orbitals are very efficient for density functional calculations but lack a systematic variational convergence.   We present a variational method to optimize numerical atomic orbitals using a single parameter to control their range.   The efficiency of the basis generation scheme is tested and compared with other schemes for multiple zeta basis sets.   The scheme shows to be comparable in quality to other widely used schemes albeit offering better performance for linear-scaling computations. 
E. Anglada, J. Soler, J. Junquera and E. Artacho