Calculations of magnetic properties. II. Electron-correlated nuclear shielding constants for nine small molecules

Abstract

Calculations of the nuclear magnetic shielding constants at the self-consistent-field (SCF) and second-order Mo/ller–Plesset (MP2) levels of theory are reported for H2, N2, F2, HF, CO, HCN, HNC, H2O, and NH3. The reliability of the calculations is verified by the high degree of satisfaction of the appropriate sum rule. The second-order correlation corrections to the shielding constants are found to be particularly important for the multiply bonded atoms in molecules such as N2, CO, HCN, and HNC. Vibrational corrections to the shielding constants for the diatomic molecules are shown to be significant.