Other Approaches to Gauge Invariance

In calculations on small molecules the basis sets have in recent years approached the completeness condition and under these circumstances gauge invariance will be achieved automatically without introducing expheit transformations of the localized orbitals. Such procedures impose very heavy demands on computation time. 

Lazzeretti has also employed the Bloch gauge, which expands the vector potential in terms of multipoles, to develop a systematic theory of the molecular response to electromagnetic fields. 

5 Ab initio Calculations of Magnetic Response to 1999. - A number of groups have contributed to the implementation of magnetic property calculations 

Gauss has performed correlated calculations at MP2 leveP and Gauss and Stanton at CCSD level.  

---