Vibrational analysis of 4-amino pyrazolo (3,4-d) pyrimidine A joint FTIR, Laser Raman and scaled quantum mechanical studies

► A detailed interpretation of the infrared and Raman spectra of [4AP(3,4-D)P] is also reported. ► The calculated HOMO and LUMO energies shows that charge transfer occur within the molecule. ► The theoretical FT-IR and FT-Raman spectra for the title molecule have also been constructed.