Resonance in chemical reactions is a very intriguing quantum mechanical phenomenon and provides essential information about the detailed shape of the potential-energy surfaces especially near the nuclear configuration that is critical for dynamical constraints.[1] Fano-type resonance is particularly interesting since it results from the interference of two distinct reactive pathways leading to the same product channel. [2] When an atom is excited to a super-excited state above the ionization threshold energy, and for instance, the isoenergetic continuum is coherently excited at the same time, this results in the interference of direct and indirect ionization processes to give the asymmetric line shape in the ionization cross section.[3] Fano resonance has often been found in the ionization cross section of atoms, whereas its observation in the molecular systems is very rare, especially in gas-phase dynamics. Only a few cases have been reported to date in vibrational autoionization of H 3 [4] or predissociation of H 2 , [5] Cs 2 , [6] and FNO. [7] The multidimensionality of the internal coordinate of polyatomic molecules generally makes the observation of the Fano resonance more difficult since the coherent excitation of bound and continuum states is less probable when the number of internal degrees of freedom increases. The intrinsic spectral congestion of polyatomic molecules may also hamper the experimental observation of asymmetric resonance. Consequently, Fano resonances in polyatomic systems have rarely been interrogated in chemical reactions. Herein, we report the observation of Fano profiles in the partial photodissociation cross section of the diazirine. The yield of the nascent 1 CH 2 (B ) fragment from the S 1 state of diazirine has been monitored as a function of the excitation energy by detecting the total fluorescence emitting in the 1 CH 2 (B ) to 1 CH 2 (ffi) transition. All of the Franck-Condon active bands show asymmetric line shapes, giving the modedependent dynamic parameters, such as homogeneous line width, center of resonance frequency, and the asymmetry parameter. The symmetric and asymmetric C À N stretching modes exhibit quite different Fano profiles, giving qualitative and yet essential information about the shape of the potentialenergy surface in the vicinity of the transition state. Especially since the interference in the reaction pathways could be further utilized to control the outcomes of chemical reactions, [7] the experimental finding of the Fano resonance in a polyatomic molecule may open the possibility of controlling the reaction of complicated molecular systems in multidimensional coordinates through the manipulation of the phase involved in the excitation process.Diazirine (CH 2 N 2 ), as a clean source of carbene and a precursor of diazomethane, [8] has been intensively studied theoretically. However because of the lack of experimental studies, even the structure and dephasing mechanism of diazirine in the first electronically excited state (S 1 ) are still the subject of...

Nitrogen and sulfur adsorption/chemisorption on LiFePO4 particles is characterized by DFT calculations and time of flight secondary ion mass spectrometry.