  We present a computational method to accurately calculate Raman spectra from
first principles with an at least one order of magnitude higher efficiency.
This scheme thus allows to routinely calculate finite-temperature Raman spectra
"on-the-fly" by means of \textit{ab-initio} molecular dynamics simulations. To
demonstrate the predictive power of this approach we investigate the effect of
hydrophobic and hydrophilic solutes in water solution on the infrared and Raman
spectra.
