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Basis Set to analyze a molecule that involves silver
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Adam Moss
Basis Set to analyze a molecule that involves silver
Firstly, 6-311+G** for C,H,F is usually good enough for DFT calculations (assuming you are using DFT). If F elements are the only possible elements which can be or become anion F- in your studied system, there is a more computationally cost-effective scheme: using 6-311G** for C,H and 6-311+G* for F. Proper diffuse functions can often save computational cost and avoid possible convergence issues in SCF or CP-SCF.
Secondly, LANL2DZ for Ag is somewhat small/insufficient, especially for computational resource nowadays. LANL2TZ or def2-TZVP would be better. If your system contains <50 atoms, using LANL2TZ(f) for Ag is also a good choice, especially if your Ag is involved in catalysis.
Thirdly, "the geometry did not converge for the given CPU space" is hard to tell why. For example, a wrong syntax of LANL2 ECP written in the input file may lead to strange behavior of geometry optimization. So you may want to post your input file (no need to show Cartesian coordinates) and we can check if there is anything inappropriate.
Firstly, 6-311+G** for C,H,F is usually good enough for DFT calculations (assuming you are using DFT). If F elements are the only possible elements which can be or become anion F- in your studied system, there is a more computationally cost-effective scheme: using 6-311G** for C,H and 6-311+G* for F. Proper diffuse functions can often save computational cost and avoid possible convergence issues in SCF or CP-SCF.
Secondly, LANL2DZ for Ag is somewhat small/insufficient, especially for computational resource nowadays. LANL2TZ or def2-TZVP would be better. If your system contains <50 atoms, using LANL2TZ(f) for Ag is also a good choice, especially if your Ag is involved in catalysis.
Thirdly, "the geometry did not converge for the given CPU space" is hard to tell why. For example, a wrong syntax of LANL2 ECP written in the input file may lead to strange behavior of geometry optimization. So you may want to post your input file (no need to show Cartesian coordinates) and we can check if there is anything inappropriate.
Firstly, 6-311+G** for C,H,F is usually good enough for DFT calculations (assuming you are using DFT). If F elements are the only possible elements which can be or become anion F- in your studied system, there is a more computationally cost-effective scheme: using 6-311G** for C,H and 6-311+G* for F. Proper diffuse functions can often save computational cost and avoid possible convergence issues in SCF or CP-SCF.
Secondly, LANL2DZ for Ag is somewhat small/insufficient, especially for computational resource nowadays. LANL2TZ or def2-TZVP would be better. If your system contains <50 atoms, using LANL2TZ(f) for Ag is also a good choice, especially if your Ag is involved in catalysis.
Thirdly, "the geometry did not converge for the given CPU space" is hard to tell why. For example, a wrong syntax of LANL2 ECP written in the input file may lead to strange behavior of geometry optimization. So you may want to post your input file (no need to show Cartesian coordinates) and we can check if there is anything inappropriate.
Firstly, 6-311+G** for C,H,F is usually good enough for DFT calculations (assuming you are using DFT). If F elements are the only possible elements which can be or become anion F- in your studied system, there is a more computationally cost-effective scheme: using 6-311G** for C,H and 6-311+G* for F. Proper diffuse functions can often save computational cost and avoid possible convergence issues in SCF or CP-SCF.
Secondly, LANL2DZ for Ag is somewhat small/insufficient, especially for computational resource nowadays. LANL2TZ or def2-TZVP would be better. If your system contains <50 atoms, using LANL2TZ(f) for Ag is also a good choice, especially if your Ag is involved in catalysis.
Thirdly, "the geometry did not converge for the given CPU space" is hard to tell why. For example, a wrong syntax of LANL2 ECP written in the input file may lead to strange behavior of geometry optimization. So you may want to post your input file (no need to show Cartesian coordinates) and we can check if there is anything inappropriate.
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