The Study On Spectroscopic Properties Of CF~- And CN

Carbon is one of the elements which are found and used by human beings.Carbide includes many important inorganic molecules（such as CO₂ CH₄ and CN）and inorganic molecules that constitute of organism,so it is closely bound up with our lives.As the simplest carbide,diatomic molecules composed of carbon atom attracted widely attention from the researchers.Spectroscopy is finger print of molecule,and directly illustrates the internal structure of molecule.Therefore the spectroscopic properties are still research focus studied by both theoretical calculations and experimental measurements.In this thesis,the CF^-is investigated by ab initio and the spectra of CN radical is observed and analyzed by laser induced breakdown spectroscopy（LIBS）.In theory,CF^-anion was calculated by the MOLPRO quantitative calculation software.Based on consistent basis set aug-cc-pV5 Z,five low-lying potential energy curves（PECs）X3Σ-,a1Δ,b1Σ+,A³П and c1П of CF^-have been calculated by using internally contracted multi-reference configuration interaction（icMRCI）approach.In order to improve the reliability of data,Davidson modification and scalar relativistic correction are considered in the calculation.According to ?-S state potential energy curves,ro-vibrational levels of theses electronic states are derived through solving the radial Schr（?）dinger equation,and then the molecular parameters（Te,Re,ωe,ωeχe,Be,αe,De）are obtained by fitting.In addition,the electric dipole moment curves of five Λ-S states for CF^-anion was computed,analyzing the influence of electronic state configuration changes to the electric dipole moments.Then,we calculated the A³П–X3Σ-transition dipole moment and the Franck-Condon factors,obtaining the A³П five lying vibration energy levels of radiation life τ,and discussed the transition properties between the two triplet-states,giving the oscillator strength f00.Finally,we studied the predissociation mechanism of A³П state,and calculated the high vibration level dissociation lifetime τd.In experiment,we use LIBS to obtain the vibrational spectra for B²Σ⁺–X²Σ⁺ system of CN free radicals.Graphite samples was ablated by adopting Nd: YAG laser with Q-switch in the air,and the laser was focused 0.5 mm upon than that of the target in order to dissociate C atoms in the graphite samples and N₂ molecules at the same time.Then C and N atoms in the plasma combined into CN free radicals and the spontaneously radiated to the low state.We collected the fluorescence into the spectrometer and derive the ro-vibrational spectral bands of B²Σ⁺–X²Σ⁺ for CN radicals.The vibration and rotation temperature of CN are 4600 K and 4400 K respectively,through fitting the recorded spectra employing LIFBASE software.