ZINTEGROWANE BADANIA SPEKTROSKOPOWO-TEORETYCZNE: ROLA OBLICZEŃ ANHARMONICZNYCH W ANALIZIE KONFORMACYJNEJ CZĄSTECZEK NA PRZYKŁADZIE IZOMERU GLICYNY - KWASU ACETOHYDROKSAMOWEGO (AHA)

Anharmonic infrared spectra of the two conformers of a glycine isomer, acetohydroxamic acid (AHA), have been compared with experimental MI-FTIR spectra, confirming the 1Z → 1E transition upon irradiation at 225 nm. GVPT2 computations at the revDSD-PBEP86/jun-cc-pVTZ level lead to overall good agreement with experiment with mean errors of about 10-12 cm-1, allowing also assignment of several bands to the non-fundamental transitions. It is shown that, due to the different structure and wavenumbers corresponding to fundamental vibrations, the 1Z and 1E conformers show distinct resonance patterns. This work highlights advantages provided by anharmonic computations accounting for the intensities of non-fundamental transitions. Keywords: