Electrons pseudopotential

The calculations for the CI2 molecule were performed at the all-electron, pseudopotential and combined levels. In the latter case, the pseudopotential and pseudofunctions were chosen at only one of the chlorine atoms. Such a variant could be considered as a prototype for large-scale cluster computations where external coordination shells of a cluster have to be replaced by pseudoatoms, whereas the innermost "important area is represented by the all-electron atoms. Table 3 shows that the combined approach does not lead... 

P. Schwerdtfeger, T. Fischer, M. Dolg, G. Igel-Mann, A. Niddass, H. Stoll, A. Haa-land, The accuracy of the pseudopotential approximation. I. An analysis of the spectroscopic constants for the electronic ground states of InCl and InCls using various three valence electron pseudopotentials for indium, J. Chem. Phys. 102 (1995) 2050-2062. 

Figure 13. Valence spinors of the Db atom in the 6d 7s ground state configuration from average-level all-electron (AE, dashed lines) multiconfiguration Dirac-Hartree-Fock calculations and corresponding valence-only calculations using a relativistic energy-consistent 13-valence-electron pseudopotential (PP, solid lines). A logarithmic scale for the distance r from the (point) nucleus is us in order to resolve the nodal structure of the all-electron spinors. The innermost parts have been truncated.

Molecular constants of selected Ge diatomics obtained with energy-consistent four-valence electron pseudopotential (PP) [197] and a core-polarization potential (CPP) [188] in connection with the optimized cc-pVnZ (n=T,Q) valence basis sets of Martin and Sundermann [241]. The label > denotes the result of an extrapolation to the basis set limit. 

In this section we report some theoretical work on the molecular spectroscopy in rare gas matrices. Due to the difficulty in modelling the environment, theoretical studies for a long time compared the results obtained from gas phase calculations with experimental data in matrices. However, it has been demonstrated that the effect of the matrix is not negligible, and may strongly depend on the rare gas, as discussed recently by Li et al [186]. Even if relativistic pseudopotentials lead to a substantial reduction of computational costs, one still needs to treat explicitly a certain number of valence electrons, for instance eight electrons for each rare gas (Rg) atom. A further simplification is to consider a rare gas atom as a zero-electron system with all its electrons in the core represented by the so-called zero-electron pseudopotential or e-Rg pseudopotential (for further details see Grofi and Spiegelmaim [187,188] and references therein). As... 

Pseudopotentials are usually derived from all-electron atomic calculations. The valence electron pseudopotential is then required to reproduce the behaviour and properties of the valence electrons in the full calculation. For example, the energy levels with the pseudopotential should be the same as for the all-electron calculation. In addition, the pseudopotential will often depend upon the orbital angular momentum of the wavefimction (i.e. for s, p, d, etc. orbitals) and it will be desired that the total valence electron density within the core radius equals that in the all-electron situation. Such pseudopotentials are... 

Quasirelativistic 11 valence electron pseudopotentials for La and Lu. Basis sets La,Lu (8s7p6d60, H (8s4p3d2f), 0,F (13s7p4d3f2g) Dolg (1995). 

Environment-Reflecting (Environment-Adaptive, All-Electron) Pseudopotentials... 

More about the all-electron pseudopotential technique can be found in [10] (Fig. 12.1). 

Vackaf J, Simflnek A (2003) Adaptability and accuracy of aU-electron pseudopotentials. Phys RevB 67 125113... 

J. M. Herbert and L. D. Jacobson,/. Fhys. Chem. A, 115,14470-14483 (2011). Structure of the Aqueous Electron Assessment of One-Electron Pseudopotential Models in Comparison to Experimental Data and Time-Dependent Density Functional Theory. 

The leading term corresponds to the Coulomb attraction between the valence electrons and the cores, and the expression Vpp of the second term is the one-electron pseudopotential operator. This operator keeps the valence electrons out of the core and in the valence space, i.e., it is repulsive in the short-range and attractive in the long-range [6]. The main task for the PP development is now to find an analytical form, i.e., a suitable parametrization. 

---