THE CALCULATION OF SE-77 CHEMICAL-SHIFTS USING GAUGE INCLUDING ATOMICORBITALS AND DENSITY-FUNCTIONAL THEORY

Calculations of Se-77 nuclear magnetic resonance chemical shifts and s hieldings are reported for a number of selenium containing compounds. The calculated shifts span a range of about 2800 ppm, and therefore co ver almost the complete range of known Se-77 chemical shifts. The calc ulations are based on density functional theory (DFT); gauge including atomic orbitals (GIAO's) are used. The DFT-GIAO method is tested agai nst other theoretical approaches. It is able to predict chemical shift s as well as individual tensor components of the shielding tensor with about the same quality as sophisticated ab initio methods. DFT is eve n capable of handling highly correlated systems like Se-4(2+). Other m ethods fail in this particular case. (C) 1996 American Institute of Ph ysics.