Harmonic Infrared and Raman Spectra in Molecular Environments Using the Polarizable Embedding Model


Karen Oda Hjorth Minde Dundas, Maarten T. P. Beerepoot, Magnus Ringholm, Simen Reine, Radovan Bast, Nanna Holmgaard List, Jacob Kongsted, Kenneth Ruud, Jógvan Magnus Haugaard Olsen

J. Chem. Theory Comput., 2021, 17, 3599


We present a fully analytic approach to calculate infrared (IR) and Raman spectra of molecules embedded in complex molecular environments modeled using the fragment-based polarizable embedding (PE) model. We provide the theory for the calculation of analytic second-order geometric derivatives of molecular energies and first-order geometric derivatives of electric dipole moments and dipole–dipole polarizabilities within the PE model. The derivatives are implemented using a general open-ended response theory framework, thus allowing for an extension to higher-order derivatives. The embedding-potential parameters used to describe the environment in the PE model are derived through first-principles calculations, thus allowing a wide variety of systems to be modeled, including solvents, proteins, and other large and complex molecular environments. Here, we present proof-of-principle calculations of IR and Raman spectra of acetone in different solvents. This work is an important step toward calculating accurate vibrational spectra of molecules embedded in realistic environments.