Benchmarks and Workflow for Harmonic IR and Raman Spectra

We present a workflow, benchmarks, and applications to provide a roadmap for simulating harmonic IR and Raman spectra for large solute-solvent systems by employing a polarizable-embedding quantum-mechanics (PE-QM) approach. This multiscale modeling scheme divides the system into a central core region described by quantum-mechanical methods and an environment region described through the fragment-based polarizable embedding (PE) model. The workflow involves generating representative structures, calculating properties, and post-processing data. Benchmark calculations quantify errors introduced by some of the key approximations used in our approach and discuss its strengths and weaknesses. Finally, we apply the workflow to acetone in three different solvents, comparing simulated spectra to experimental results to further evaluate our approach and identify potential weaknesses. Accurate simulations of solute-solvent systems are an important step toward modeling more complex molecular systems with a fragment-based PE approach.