Quantum chemistry study on fluorescence spectra of three kinds of amino acids

Quantum chemistry calculation of fluorescence spectrum offers certain theoretical reference for designing and selecting fluorescent analysis methods of amino acids . A theoretical study on fluorescence spectra of three kinds of amino acids by semi-empirical AM1 is given in this paper. After geometries of the three compounds are optimized, it is known that the titled compounds have rigid planar construction and big unlocalized π bond from structural parameters. For all optimal geometries, there is no imaginary frequency in vibrational analysis, which proves that the geometric configurations of the three compounds are stable. On this basis, the electronic spectra have been calculated by CIS method. All calculated results are basically consistent with experimental values.