We utilized UV resonance Raman (UVRR) measurements and density functional theory (DFT) calculations to relate the AmII'p frequency to the psi angle. The AmII'p frequency shifts by similar to 25 cm(-1) as the psi angle is varied over allowed angles of the Pro peptide bond. The AmII'p frequency does not show any significant dependence on the 99 dihedral angle. The conformation sensitivity of the AmII'p frequency derives from conformation-induced changes in the planarity of the Pro peptide bond; psi angle changes push the amide nitrogen out of the peptide bond plane. We use this AmII'p frequency dependence on the phi angle to track temperature-induced conformation changes in a polyproline peptide. The temperature-induced 7 cm(-1) downshift in the AmII'p frequency of the polyproline peptide results from an similar to 45 degrees rotation of the psi dihedral angle from psi = 145 degrees (ideal PPII conformation) to psi = 100 degrees (collapsed PPII conformation).