SPectroscopy Informed Configurational Enhanced Sampling (SPICES)

We present a new enhanced-sampling scheme for obtaining the underlying conformer starting from a spectrum: the SPectroscopy Informed Configurational Enhanced Sampling (SPICES) method. SPICES is driven by a history-dependent biased molecular dynamics, in which the biases are governed by spectral information rather than by energetic considerations. The performance of SPICES is hence rather insensitive to the target conformer’s relative energy compared to the global minimum structure. Furthermore, it does not require pretraining or prior knowledge of the system. We have critically assessed the performance of SPICES and demonstrated that it can identify the correct conformer of our test system, diphenylalanine (FF), among the 400 stable conformations in 22 spectral calculations (median value). We also show that SPICES is robust to noise in the experimental spectrum and to small discrepancies between theory and experiment.