TY  - JOUR
A1  - Engels, Bernd
T1  - Estimation of the influence of the configurations neglected within truncated MR-CI wavefunctions on molecular properties
N2  - Reliable prediction of the isotropic hyperfine coupling constant, a\(_{iso}\), is still a difficult task for ab initio calculations. Strong dependence on the method used for its calculation is found. Within a truncated multi-referencc ansatz a\(_{iso}\) is strongly affected by the size ofthe reference space and the nurober of terms in the truncated Cl expansion. In the present paperdifferent effects of the neglected Cl space are discussed. Modified B\(_K\) and A\(_K\) methods are used to estimate the contributions ofthe neglected configurations. lt can be shown that a combination of both methods is able to recover about 90-9 S% of the total error in a\(_{iso}\)· Furthermore, it was found that to obtain about 90% of the B\(_K\) correction only about I 0-20% ofthe configurations within H0 have to be corrected.
KW  - Organische Chemie
Y1  - 1991
UR  - https://opus.bibliothek.uni-wuerzburg.de/frontdoor/index/index/docId/5175
UR  - https://nbn-resolving.org/urn:nbn:de:bvb:20-opus-58890
ER  -