For simply to perform any gaussian calculation in solvent phase and anion state or cation state , what should i optimize either solvent phase or anion state to obtain more precise result.
When performing Gaussian calculations for a molecule in different phases (e.g., gas and solvent) or different states (neutral, anion, or cation), the optimization strategy may vary based on your specific goals.
Gas Phase Optimization:Optimize the molecular structure in the gas phase first to obtain a reasonable starting point. This step allows you to understand the geometry and electronic structure of the molecule without the influence of solvent or charge.
Solvent Phase Optimization:After gas phase optimization, perform a solvent phase optimization. Include solvent effects in the calculation, such as using solvation models (e.g., PCM, SMD) or explicit solvent molecules. Solvent phase optimization is crucial for understanding the molecule's behavior in a realistic environment.
Charge State Optimization:If you are studying different charge states (anion or cation), you can perform separate optimizations for each charge state. Optimize the molecular structure for the neutral state first, and then adjust the charge accordingly for anion or cation optimizations.
Combined Optimization:In some cases, you may perform a combined optimization, considering both solvent effects and charge state simultaneously. This approach provides a more comprehensive understanding of the molecule's behavior under specific conditions.
It's generally a good practice to iteratively refine your calculations based on the obtained results. Keep in mind that the choice of basis set, level of theory, and the solvent model can significantly impact the accuracy of your calculations. Always validate your results against experimental data when available and consider the specific requirements of your research or study.