Hiromichi Uehara

The ν1 band of the DO2 radical by difference frequency laser and diode laser spectroscopy: The equilibrium structure of the hydroperoxyl radical

The ν1 band of the DO2 radical was observed by difference frequency laser and diode laser spectroscopy with Zeeman modulation. The radical was produced by a 60 Hz discharge in a mixture of CH3OD or CD3OD and O2 flowing through a multiple reflection absorption cell. The observed lines, 181 in total, of six subbands with Ka =2←3, 1←2, 0←1, 1←0, 2←1, and 3←2 were included in a least‐squares analysis to determine molecular parameters for the upper state: A=326 929.3(92), B=31 683.68(36), C=28 779.96(46), eaa=−26 039(38), ebb=−381.7(29), ecc =4.3(22), in MHz, and the band origin ν0=2 549.224 65(36) cm−1, where the values in parentheses denote one standard error in units of the last quoted decimal place. By combining this data with that for the ν2 and ν3 bands of DO2 by Uehara et al. and that for HO2 already available in the literature, the equilibrium structure of the hydroperoxyl radical was calculated with estimated uncertainties: re (O–H)=0.9707±0.0020 A, re(O–O)=1.330 54 ±0.000 85 A, and θe (HOO)=104.29±0....

Diode laser spectroscopy of the ν3 and ν2 fundamental bands of DO2

The diode laser spectrum and the IR LMR spectrum of the ν3 fundamental band (O–O stretch) of DO2 were observed, as well as the diode laser spectrum of the ν2 fundamental band (D–O–O bend). Simultaneous analysis of the ν3 and ν2 bands has yielded the molecular constants for the (001) and (010) states and the Coriolis coupling constant. These, together with other available molecular constants for DO2 and HO2 were used to derive the equilibrium molecular structure of the HO2 radical, as already reported [K. G. Lubic et al., J. Chem. Phys. 81, 4826 (1984)]. The harmonic force field obtained in the present study has explained well the general features of the Coriolis coupling constant, quartic centrifugal distortion constants, and the inertia defects for DO2.

Laser‐induced fluorescence spectrum of the CCN radical with an Ar+ laser

The laser‐induced fluorescence (LIF) spectrum of the CCN radical was observed with an Ar+ laser. The laser line of 465.8 nm coincided with two rovibronic transitions: R1 (23.5) and sR21 (12.5) for A2Δi:(010)Φ−X 2Πr:(010)Δ. The LIF spectrum consisted of the resonant series: A2Δi:(010)Φ−X 2Πr: (v1v2v3)Δ, and the collision‐induced bands: A2Δi:(010)Π−X 2Πr:(v11v3)Σ+, Σ−. The analysis yielded the vibrational and the vibronic parameters of the ground electronic state X 2Πr.

A stark-sweep microwave cavity spectrometer for Zeeman effect studies and for pollutant monitoring

Abstract A microwave cavity spectrometer of the Stark-dc-voltage sweep type with a fixed resonance frequency in the X-band region is described. The spectrometer was applied to the study of the Zeeman effect in molecules as well as to pollutant monitoring.

Laser magnetic resonance for the v = 1 ← 0 transition of NO (2Π32) by CO laser

Abstract The vibration-rotation transitions for v = 1 ← 0 of NO ( 2 Π 1 2 ) have been studied by using the technique of laser magnetic resonance spectroscopy. Five magnetic resonance lines are observed with three CO laser lines in the range from 1859 to 1886 cm −1 . From these, three zero-field transition frequencies, v = 1 ← 0; R( 3 2 ) , P( 7 2 ) , and P( 9 2 ) are obtained with an accuracy of ±0.0007 cm −1 . The molecular constants which have been determined by borrowing centrifugal constants from a previous infrared work are B 02 ∗ = 1.72004 ± 0.00006 cm −1 , B 12 ∗ = 1.70212 ± 0.00010 cm −1 , and G(v = 1) − G(v = 0) ( for 2 Π 1 2 ) = 1875.8470 ± 0.0007 cm −1 .

Laser magnetic resonance spectra of ClO2 tuned by the avoidance of zeeman level crossing

Abstract LMR of the ν 1 band of the stable ClO 2 radical has exhibited clearly-resolved spectra under strong magnetic fields. Some of these were well described by a new type Zeeman-tuning due to the avoidance of the Zeeman level crossing.

Vibronic Effect on the Mean‐Square Amplitudes of Internuclear Distances in a Tetrahedral Molecule

A quantitative relation has been derived for the mean‐square amplitudes of internuclear distances in a tetrahedral XY4 molecule when vibronic interactions are present. The calculation has revealed that, first, the mean‐square amplitude lY—Y increases by the presence of vibronic interactions and second, the effect is large when the frequency of the degenerate vibration ν2 is low.

Infrared diode laser spectroscopy of a high-temperature molecule: GeSe

Abstract The vibrational-rotational spectrum of GeSe has been observed with diode laser spectrometer equipped with a single pass cell of heat-pipe oven type. About 770 spectral lines for the Δv = 1 band sequences of six isotopomers of GeSe have been assigned between 380 to 420 cm −1 . These data have been analyzed in combination with 138 microwave data from the literature by two different methods of least-squares fit to different potential functions. The qualities of the fits are nearly equal. The value of ω e is determined to be 402.66129(70) cm −1 for 74 Ge 80 Se.

Laser‐induced fluorescence spectrum of the CCN radical. II. Excitation of A 2Δi:(010)Π–X 2Πr:(010)Σ− vibronic band

The laser‐induced fluorescence (LIF) spectrum of the CCN radical was observed with a CW dye laser tuned to the P branch head of the vibronic band of A 2Δi:(010)Π–X 2Πr:(010)Σ−. The LIF spectrum consisted of two resonant transitions of nearly equal intensity: A 2Δi:(010)Π–X 2Πr:(v11v3)Σ− and A 2Δi:(010)Π–X 2Πr:(v11v3)Σ+. The observation has provided a further evidence for the assignment of the collision‐induced vibronic bands in our previous work [K. Hakuta and H. Uehara, J. Chem. Phys. xx, xxxx (xxxx)]. The analysis yielded a vibronic parameter eω2 for four vibrational states. (AIP)The laser‐induced fluorescence (LIF) spectrum of the CCN radical was observed with a CW dye laser tuned to the P branch head of the vibronic band of A 2Δi:(010)Π–X 2Πr:(010)Σ−. The LIF spectrum consisted of two resonant transitions of nearly equal intensity: A 2Δi:(010)Π–X 2Πr:(v11v3)Σ− and A 2Δi:(010)Π–X 2Πr:(v11v3)Σ+. The observation has provided a further evidence for the assignment of the collision‐induced vibronic bands in our previous work [K. Hakuta and H. Uehara, J. Chem. Phys. xx, xxxx (xxxx)]. The analysis yielded a vibronic parameter eω2 for four vibrational states. (AIP)

Laser magnetic resonance of the v = 1←0 transition of the PD (3Σ−) radical

Sixteen LMR spectra for the low N (N′, N″⩽3) transitions of the vibration (v = 1←0) band of PD (X 3Σ−) were observed by using seven 12C 16O laser lines. Analysis has yielded rotational, spin–spin, and spin–rotation constants for the v = 0 and 1 states and the band origin. The band origin ν0 has been determined to be 1653.2858(36) cm−1.