A photodissociation method for measuring the IR spectra of highly vibrationally excited molecules

Abstract A universal method is proposed for measuring the IR spectra of molecules having vibrational energy E ≳ D , where D is the dissociation threshold. The method is based on measuring small linear increments of the dissociation yield arising from irradiation of excited molecules by a weak IR pulse. The proposed experiment enables inhomogeneous broadening of the IR spectrum to be suppressed even in the case of large polyatomic molecules which may be excited significantly over the dissociation threshold.