Gaussian basis sets, convergence

Figure 1 Comparison of the convergence behaviour of the second order correlation energy component for the F anion with sequences of even-tempered Gaussian basis sets containing s- and p-type functions designed for the neutral F and Ne atoms with the behaviour of this component for the Ne atom. The cmrves are labelled as follows - (a) AE2 Ne [A e]) (b) AE2 F -, [iVe]) (c) AEtiF--, [F]).

Fig. 3. The four panels show the correlation between all forces Fx, Fy, and Fz calculated for the same configuration of a liquid water sample containing 32 water molecules. Panel A shows that perfect agreement can be obtained between GPW (QS) and CPMD using large basis sets (see text) for both methods Panel B compares these converged results to CPMD results using slightly more typical settings Panel C shows the effect of a smaller Gaussian basis set Panel D additionally shows the effect of a smaller density cut off...

The choice of the value of the coherent state width 7 is arbitrary, since this parameter does not affect the mathematical properties of the Gaussian basis set which determine the form of the semi-classical propagator. In fact, the value of this quantity is usually chosen in practical implementations so as to facilitate the numerical convergence. In the following, we shall set 7 = 1/2 since with this choice (25) simplifies considerably and becomes... 

Convergence of the ground state energy of the hydrogen molecular ion using a systematic sequence of distributed even-tempered Gaussian basis sets. 

Gaussian Basis Sets Exhibiting Systematic Convergence to the Complete Basis Set Limit... 

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