The basic approximation of the MNDO method is applied to the SCF-MO theory of nu-clear magnetic shielding constants.Gauge-invariant atomic orbitais（GIAO）and derived equations are used to cal-culate NMR chemical shif...The basic approximation of the MNDO method is applied to the SCF-MO theory of nu-clear magnetic shielding constants.Gauge-invariant atomic orbitais（GIAO）and derived equations are used to cal-culate NMR chemical shifts.A more simple and effective calculation of integration for operators 1/r<sub>M</sub>,L<sub>M</sub> andL<sub>M</sub>/r<sub>M</sub> described in our previous paper is used.By proper selection of MNDO parameters together with thetwo-center approximation,a satisfactory agreement between computational and experimental <sup>13</sup>C and <sup>19</sup>F chemi-cal shifts is obtained for a representative set of fluorides.展开更多
文摘The basic approximation of the MNDO method is applied to the SCF-MO theory of nu-clear magnetic shielding constants.Gauge-invariant atomic orbitais（GIAO）and derived equations are used to cal-culate NMR chemical shifts.A more simple and effective calculation of integration for operators 1/r<sub>M</sub>,L<sub>M</sub> andL<sub>M</sub>/r<sub>M</sub> described in our previous paper is used.By proper selection of MNDO parameters together with thetwo-center approximation,a satisfactory agreement between computational and experimental <sup>13</sup>C and <sup>19</sup>F chemi-cal shifts is obtained for a representative set of fluorides.
