High-resolution Spectroscopy Combined with Laser, Molecular Beam and Magnetic or Electric Field, and Dynamics of Excited Molecules

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We have constructed a single mode auto-scan laser system which works in UV-Visible-NearIR region. An actively stabilized etalon is used to measure the absolute wavenumber of laser line, and the accuracy better than 0.0001cm^<-1> is obtained. The jitters of frequency of the scanning laser is reduced by locking the laser cavity to a stabilized external cavity, and the line width is reduced to 0.00002cm^<-1>. We developed new experimental methods by combining the laser, a molecular beam, and the external magnetic or electric field.1. We have studied the structure and the dynamics of excited molecules by using techniques of ultra-high resolution spectroscopy. We found a new interference effect in predissociation which is a quantum effect in photodissociation. It shows the importance of phases of wave functions whose levels concerns a chemical reaction.2. We extended the high-resolution spectroscopy for polyatomic molecules, such as CS_2, glyoxal, and pyrazine. We measured a Doppler-free tw … More o-photon absorption apectrum of glyoxal. The spectrum is completely assigned and the molecular constants are determined. With accuracy better than 100 times than previous studies, we could study small perturbations and the effect of magnetic field even at 5 gauss. These studies opened a new field of spectroscopy which uses the intensity and energy shift.3. Cs_2 molecules were excited to the single level D^1SIGMA^+_ (v=46, J=54), which predissociated to Cs (6s^2S_<1/2>) + Cs(6p^2P_<3/2>) atoms. The m_j-resolved excitation spectra of the Cs(8s^2S_<1/2, m'j>, *6p^2P_<2/3, mj>) transition in a magnetic field. This is the first report concerning the m_j-resolved Doppler line shape.4. Many levels are excited simultaneously in a ultra-first spectroscopy, but we can get lifetime or predissociation rate of a single level in a high-resolution spectroscopy. We measured the rotationally resolved line shapes of predissociating levels, and the predissociation was studied by using supplementaly the results of time-resolved spectroscopy and high-resolution spectroscopy. Less