(Color online) An isosurface of EPLF for dimethylamine showing the electron pair on top of nitrogen (center-top feature). The constant value of EPLF of 0.093 shows small localization. EPLFs are calculated from QMC walkers.
(Color online) EPLF color coded values on an isosurface of electronic density for trimethylamine. In this series, that shows decreasing values of the density, features of the EPLF are clearly seen: the atomic cores, the maximum along the bond, and the electron pair, for instance. Note how prevalent is the proton signature. EPLFs are calculated from QMC walkers.
Atomization energies for ammonia , methylamine (MA), dimethylamine (DMA), and trimethylamine (TMA) from various calculations. Numbers are differences with the experimental value at ( in kJ/mol). Total energies are corrected by zero point energy (ZPE). For the present calculation an estimated ZPE of 0.03, 0.06, 0.09, and for , MA, DMA, and TMA, respectively, were used. Except for the original calculations of the last row, all data come from Ref. 33.
QMC atomization energies for the molecules studied in this work at . For trifluoromethylamine a value of from a Hartree-Fock calculation is reported in Ref. 36. Density functional theory with B3LYP treatment of exchange and correlation was performed for fluoroamine but atomization energies were not reported in Ref. 37.
Descriptors of the electron pair basin. The second and third columns list the integral of the electronic density within the lone pair basin for the LDA and QMC densities, respectively. The fourth column lists the distance between the nitrogen nucleus and the centroid of the ELF (calculated using the LDA density), and the last column lists the volume of the basin.
Expectation values of EPLF0 and EPLF3 projected on the lone pair molecular orbital. The fourth column is the volume of the region where EPLF3 is greater than within the orbital that contains the lone pair, i.e., the localization of the pair of electrons. EPLFN are calculated from QMC walkers.
Total EPLF and EPLF3 integrated on the basin of the lone electron pair defined by ELF by direct evaluation of the DMC walkers and by extrapolation (ext). is the distance of the centroid to the nitrogen nucleus for EPLFN, calculated from QMC walkers.
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