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51.
Laser-induced fluorescence (LIF) excitation spectra of the B-X (2)A(") electronic transition of the CH(2)CHS radical, which is the sulfur analog of the vinoxy (CH(2)CHO) radical, were observed under room temperature and jet-cooled conditions. The LIF excitation spectra show very poor vibronic structures, since the fluorescence quantum yields of the upper vibronic levels are too small to detect fluorescence, except for the vibrationless level in the B state. A dispersed fluorescence spectrum of jet-cooled CH(2)CHS from the vibrationless level of the B state was also observed, and vibrational frequencies in the X state were determined. Precise rotational and spin-rotation constants in the ground vibronic level of the radical were determined from pure rotational spectroscopy using a Fourier-transform microwave (FTMW) spectrometer and a FTMW-millimeter wave double-resonance technique [Y. Sumiyoshi et al., J. Chem. Phys. 123, 054324 (2005)]. The rotationally resolved LIF excitation spectrum for the vibronic origin band of the jet-cooled CH(2)CHS radical was analyzed using the ground state molecular constants determined from pure rotational spectroscopy. Determined molecular constants for the upper and lower electronic states agree well with results of ab initio calculations. 相似文献
52.
Electronic spectra of the C3N radical have been observed for the first time in the near ultraviolet wavelength region by laser induced fluorescence (LIF) spectroscopy. Seventeen vibronic bands of the B 2Pii-X 2Sigma+ electronic transition system of C3N were identified in LIF spectra of products in a discharge of HC3N. The origin of the B 2Pii state was determined to be 27,929.985(1) cm(-1) from rovibrational analyses. It was found that observations of two types of 2Sigma vibronic levels, which have 2Sigma+ and 2Sigma+/- symmetries originated from excitations of the nu4 trans-bending mode (omega4=369.1(20) cm(-1)) with a large Renner-Teller (RT) interaction (epsilon4=-0.1549(50)), and the nu5 cis-bending mode (omega5=163.24(84) cm(-1)) with a small Renner-Teller interaction (epsilon5=-0.0503(68)), respectively. Vibronic levels, with excitations of the C-C stretching (omega3=869.7 cm(-1)) mode, were also identified. The spin-orbit interaction constant was determined to be Aso=-36.7(50) cm(-1) from the RT analysis. In dispersed fluorescence spectra from B 2Pii, vibrational structures of the low-lying electronically excited A 2Pii state were clearly observed with a strong progression due to the nu3' mode, together with those of the X 2Sigma+ state with weak intensities. The origin of A 2Pii, T0=1844(3) cm(-1), and the vibrational frequencies, omega3'=883(3) cm(-1) and omega5'=121(3) cm(-1) for A 2Pii, and omega3"=1054(3) cm(-1), omega4"=405(3) cm(-1), and omega5"=131(3) cm(-1) for X 2Sigma+, were determined. Time profiles of fluorescence from B 2Pii have short (50-200 ns) and long (>1 micros) decay components with quantum beats, indicating that there is a competition between radiative decay and the nonradiative internal conversion to vibrationally highly excited A 2Pii and X 2Sigma+. 相似文献
53.
Yasuki Endo Keiichi Nagai Chikashi Yamada Eizi Hirota 《Journal of Molecular Spectroscopy》1983,97(1):213-219
The vibration-rotation spectra of the SF radical were observed by an infrared diode laser spectrometer. The SF radical was generated directly in a cell by glow discharge in a mixture of carbonyl sulfide and carbon tetrafluoride. Zeeman modulation and discharge current modulation were employed to discriminate SF lines from many lines of the reactants and other products. Thirty two lines were assigned to the v = 1 ← 0 and 2 ← 1 bands of both and spin states. A least-squares analysis of all the assigned lines provided precise values for molecular parameters in v = 1 and 2 and the two band origins, where ground-state constants were constrained to microwave results. The harmonic frequency ωe was thus determined to be 837.6418(13) cm?1, and the equilibrium bond length re was calculated from the Be rotational constant to be 1.596 244(22) Å with the error in parentheses, which included 2.5 standard deviations and the uncertainty of Planck's constant. 相似文献
54.
55.
Mitsutoshi Tanimoto Shuji Saito Yasuki Endo Eizi Hirota 《Journal of Molecular Spectroscopy》1984,103(2):330-336
The microwave spectrum of 28Si35Cl, the most abundant isotopic species of the silicon monochloride radical, was observed in both the and spin states of the ground vibronic state. The SiCl radical was produced in a flow cell by a dc discharge in SiCl4. The observed transitions were for both the spin states, and the observed frequencies were subjected to the least-squares analysis to yield accurate molecular constants as follows: B0 = 7652.3048(23), D0 = 0.007017(14), AJ = ?0.8392(16), p0 + 2q0 = 138.660(98), q0 = 0.20(17), , , b = 9(12), d = 46.40(94), and eQq1 = ?23.13(96), all in MHz with 3σ in parentheses. The positive sign of the Λ-doubling constant, p0, indicates that the contributions of 2Σ? states dominate over those of 2Σ+ states. The spin and orbital averages of the unpaired-electron distribution were calculated from the observed hyperfine coupling constants and were discussed in terms of the electronic structure of the molecule. 相似文献
56.
The application of femtosecond pump-probe photoelectron spectroscopy to directly observe vibrational wave packets passing through an avoided crossing is investigated using quantum wave packet dynamics calculations. Transfer of the vibrational wave packet between diabatic electronic surfaces, bifurcation of the wave packet, and wave packet construction via nonadiabatic mixing are shown to be observable as time-dependent splittings of peaks in the photoelectron spectra. 相似文献
57.
Yasuki Kikuchi Takashi Yanagawa 《Annals of the Institute of Statistical Mathematics》1988,40(2):367-379
An exact conditional test is developed for testing a trend in Poisson means when the historical control information is incorporated into the concurrent control data. An asymptotic conditional test is also developed as an alternative to the Tarone test. Asymptotic gains by the incorporation of the historical information is evaluated. 相似文献
58.
Keiichi Nagai Chikashi Yamada Yasuki Endo Eizi Hirota 《Journal of Molecular Spectroscopy》1981,90(1):249-272
The ν1 (CO stretching) and ν2 (CF stretching) bands of the FCO radical were observed with Doppler-limited resolution by an infrared diode laser spectrometer with Zeeman and source modulation. The FCO radical was generated by a 60-Hz discharge in one of the following three gas mixtures: O2 + C2F4, CO + SF6, and CO + C2F4, all diluted with He. The observed spectra were analyzed to determine the rotational constants, the centrifugal distortion constants, and the spin-rotation interaction constants. The band origins, 1861.6372(1) and 1026.1283(1) cm?1 [with standard errors in parentheses], which were obtained, were found to agree well with matrix data, 1857 and 1023 cm?1, respectively. The assignment of the observed spectra to the FCO radical was further supported by observing the ν1 band of F13CO, which was obtained from 13CO and SF6. The molecular structure and the force field of FCO are briefly discussed by using molecular constants obtained from the observed spectra. 相似文献
59.
Eizi Hirota Yasuki Endo Shuji Saito Kazuhiko Yoshida Ichiro Yamaguchi Katsunosuke Machida 《Journal of Molecular Spectroscopy》1981,89(1):223-231
The pure rotational spectra of three deuterated ethylenes, CH2CD2, CH2CHD, and cis-CHDCHD, were observed by microwave spectroscopy, and the rotational and centrifugal distortion constants were determined precisely. The dipole moment of CH2CD2 was calculated from the Stark effects to be 0.0091 ± 0.0004 D. From the observed rotational constants the average structure was calculated to be , , θz(CCH) = 121.28 ± 0.10°, and , where the errors include one standard deviation in the fitting and errors due to an uncertainty (±0.03°) in θz(CCH) - θz(CCD). 相似文献
60.
Yakabe M Nito K Yoshida M Nakazawa M Koga Y Hagimoto K Ikegami T 《Optics letters》2005,30(12):1512-1514
We describe an ultrastable cesium (Cs) atomic clock with a 9.1926-GHz regeneratively mode-locked fiber laser obtained by use of an optically pumped Cs beam tube. By adopting a 1-m-long Cs beam tube with a linewidth of 110 Hz, we have successfully obtained frequency stabilities of 4.8 x 10(-12) for tau = 1 s and 6.3 x 10(-13) for tau = 50 s for a 9.1926-GHz microwave output signal. This Cs atomic clock can generate an optical pulse train with the same stability as that of the obtained microwave, which allows us to deliver a frequency standard optical signal throughout the world by means of optical fiber networks. 相似文献