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howto:lrigpw

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howto:lrigpw [2017/05/14 13:31] dgolze [How to use it] |
howto:lrigpw [2017/05/14 13:32] (current) dgolze [How to use it] |
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Auxiliary basis sets are available for the MOLOPT basis sets. All auxiliary basis sets have been generated by simple geometric progression without any need for further optimization. These basis sets are available in different sizes: MEDIUM and LARGE. Using the large auxiliary basis sets, the accuracy is improved, but the computational overhead increases.\\ | Auxiliary basis sets are available for the MOLOPT basis sets. All auxiliary basis sets have been generated by simple geometric progression without any need for further optimization. These basis sets are available in different sizes: MEDIUM and LARGE. Using the large auxiliary basis sets, the accuracy is improved, but the computational overhead increases.\\ | ||

The LRI auxiliary basis sets are generally quite large leading to a potentially ill-conditioned overlap matrix, Equation (10) in [[doi>10.1021/acs.jctc.7b00148 | J. Chem. Theory Comput., 13, 2202 (2017)]]. The inversion of this matrix can thus be numerical instable. If the SCF is not converging, set [[inp>FORCE_EVAL/DFT/QS/LRIGPW#LRI_OVERLAP_MATRIX|LRI_OVERLAP_MATRIX]] to AUTOSELECT. In this case, the atomic pairs are identified that have extremely large condition numbers. For these pairs, the pseudoinverse instead of the regular inverse is calculated. The threshold for the condition number can be given by [[inp>FORCE_EVAL/DFT/QS/LRIGPW#MAX_CONDITION_NUM|MAX_CONDITION_NUM]].\\ | The LRI auxiliary basis sets are generally quite large leading to a potentially ill-conditioned overlap matrix, Equation (10) in [[doi>10.1021/acs.jctc.7b00148 | J. Chem. Theory Comput., 13, 2202 (2017)]]. The inversion of this matrix can thus be numerical instable. If the SCF is not converging, set [[inp>FORCE_EVAL/DFT/QS/LRIGPW#LRI_OVERLAP_MATRIX|LRI_OVERLAP_MATRIX]] to AUTOSELECT. In this case, the atomic pairs are identified that have extremely large condition numbers. For these pairs, the pseudoinverse instead of the regular inverse is calculated. The threshold for the condition number can be given by [[inp>FORCE_EVAL/DFT/QS/LRIGPW#MAX_CONDITION_NUM|MAX_CONDITION_NUM]].\\ | ||

- | The LRI integrals, Equations (31)-(34) in [[doi>10.1021/acs.jctc.7b00148 | J. Chem. Theory Comput.,13, 2202 (2017)]], are calculated prior to the SCF. The traditionally used Obara-Saika scheme is computationally too demanding here. Therefore, a more efficient integral scheme based on solid harmonic Gaussians (SHG) is employed and invoked by [[inp>FORCE_EVAL/DFT/QS/LRIGPW#SHG_LRI_INTEGRALS|SHG_LRI_INTEGRALS]], see [[doi> 10.1063/1.4973510| J. Chem. Phys., 146, 034105, 2017]] for details. | + | The LRI integrals, Equations (31)-(34) in [[doi>10.1021/acs.jctc.7b00148 | J. Chem. Theory Comput., 13, 2202 (2017)]], are calculated prior to the SCF. The traditionally used Obara-Saika scheme is computationally too demanding here. Therefore, a more efficient integral scheme based on solid harmonic Gaussians (SHG) is employed and invoked by [[inp>FORCE_EVAL/DFT/QS/LRIGPW#SHG_LRI_INTEGRALS|SHG_LRI_INTEGRALS]], see [[doi> 10.1063/1.4973510| J. Chem. Phys., 146, 034105, 2017]] for details. |

===== When to use it ===== | ===== When to use it ===== |

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