Ir and Raman spectra of L ‐aspartic acid and isotopic derivatives

The ir and Raman spectra of L‐aspartic acid, L‐aspartic‐d4 acid, and L‐aspartic‐15N acid as solid samples have been recorded and measured. The data obtained were used to propose a general assignment of the fundamental vibrational modes in the basis of the isotopic shifts measured and correlations with previous data reported for other amino acids and related molecules. A MNDO‐scaled semiempirical force field was obtained, and vibrational frequencies and descriptions were used to support the previous assignments based on experimental features.