Gamess (Quantum Chemistry software)

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SUMMARY

Specifying the symmetry of a molecule in Gamess can significantly enhance the efficiency of geometry and energy optimization by reducing the number of calculations required. This approach minimizes the degrees of freedom, allowing the program to optimize only a portion of the molecule, such as one half in cases of reflection symmetry. While some users prefer not to enforce symmetry due to output limitations, the numerical advantages in computational speed and resource usage are clear. The discussion highlights the trade-off between computational efficiency and the completeness of output data.

PREREQUISITES
  • Understanding of quantum chemistry principles
  • Familiarity with Gamess software
  • Knowledge of molecular symmetry concepts
  • Experience with geometry optimization techniques
NEXT STEPS
  • Explore the documentation for Gamess on symmetry implementation
  • Learn about geometry optimization methods in quantum chemistry
  • Investigate the differences between Gamess and Gaussian in computational efficiency
  • Study the implications of symmetry in quantum mechanical calculations
USEFUL FOR

Quantum chemists, computational chemists, and researchers optimizing molecular structures using Gamess software.

brydustin
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Just curious if there are any advantages of specifying the symmetry of a molecule when trying to optimize geometry/energy using Gamess. I previously used Gaussian (which tells you the symmetry (if your initial guess was sufficient) when the calculation is complete). But really is there any numerical advantage? Can the program "cut" the molecule in half (if for example the molecule was symmetric with respect to reflection), and just optimize that one half (quicker?). Personally, I don't like forcing symmetry in my calculations because the output only shows half the molecule, but am curious if there is any advantage to using it? thanks all...
 
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The point of using symmetry is indeed to reduce the number of calculations used, as the symmetry effectively reduces the number of degrees of freedom.
 

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