Questions tagged [geometry-optimization]

Questions about finding the molecular or material geometry that has the lowest energy.

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How does the line search in geometry optimisations work?

I am trying to write a Newton-Raphson geometry optimisation script in python (Current version of my code) using the energy, gradient and Hessian from Gaussian 16. In order to reach a minimum, I would ...
evd's user avatar
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4 votes
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How to compute only part of molecular Hessian accurately (hybrid Hessian or partial Hessian calculation)?

Hessian is required for minimisation and transition state (TS) optimisation algorithms. While the full Hessian at a certain level of theory is calculated usually for TS optimisation, usually ...
S R Maiti's user avatar
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3 votes
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Constrained geometry optmization: Molecule interacts with its surroundings

I have a water cluster(suppose) generated from MD run. Now, I want to optimize the geometry of only one water molecule of interest using QC methods (e.g. B3LYP/6-31+G(d,p)). I intend that the water ...
Pro's user avatar
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Discrepancy between Force Convergence in Geometrical Optimization and SCF Calculation in VASP: Reasons and Troubleshooting Suggestions

During a geometrical optimization of ions and lattice parameters in VASP, the forces acting on atoms were minimized to less than 0.01 eV/Å. However, when performing the subsequent self-consistent ...
Jaafar Mehrez's user avatar
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Quantum Espresso optimization calculation not converging

I have been trying to optimize the geometry of a copper based metal halide perovskite. I opened the CIF file using BURAI GUI and generated the VC-RELAX input file. I have increased the steps to be 200 ...
Kamal Nassar's user avatar
2 votes
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Wrong lattice parameter of CeO2 after structure relaxation with VASP

I am calculating the lattice parameter of CeO2 with VASP, but the optimized lattice parameter is wrong according to many references (Physical Review B 75, 035109 (2007); The Journal of Chemical ...
FaDA's user avatar
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1 vote
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LBFGS -- Incomplete Convergence due to BadIntpln

I am doing energy minimization of a molecular system in TINKER. While doing so, I am getting the error in the title of this question. What might be my problem?
Himanshu's user avatar
1 vote
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Structural phase transition under uniaxial strain

I am trying calculate a strain-induced phase transition in some weakly correlated crystalline material using Quantum Espresso (QE). The compound has two (experimentally observed) phases, one of which ...
manju9's user avatar
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maxstep Gaussian keywords

I'm running a Berny optimization and I need to include the keyword maxstep=1. Observing the output, in the convergence summary table I can see that the ...
Andrea Pellegrini's user avatar