A new ab-initio approach for NMR chemical shifts in periodic systems

We present a new method for computing NMR chemical shifts and magnetic susc eptibilities in extended systems through an ab initio density functional pe rturbation theory approach. The method is applicable to crystalline and amo rphous insulators under periodic boundary conditions, as well as to isolate d molecules. The formalism exploits the exponentially decaying nature of lo calized Wannier orbitals. We have implemented the method in the context of a plane wave pseudopotential approach. The results are in good agreement wi th experiment and with calculations that use other theoretical methods.