Masataka Mizushima

Pure rotational far-infrared transitions of 16O2 in its electronic and vibrational ground state

Abstract Five lines in the far-infrared region, due to N + 2 ← N (Δ J = 0) transitions of the 16 O 2 molecule in its ( X 3 Σ g − , v = 0) state, are measured at 773.839691, 1466.807133, 1812.405539, 2157.577773, and 2502.323923 GHz, using a tunable FIR spectrometer. The spectral lineshape of the 2.50-THz line is analyzed and the pressure self-broadening parameter of 18.2(32) kHz/Pa (=2.43(43) MHz/Torr) is obtained.

Microwave Resonance Lines of 16O2 in Its Electronic Ground State (X 3Σg

Low intensity absorption lines of 16O2, in v=0 and v=1 states, are observed in the 119 and 60 GHz regions. New sets of values for the molecular parameters, including λDD which has not been observed yet, are obtained.

High-resolution infrared Fourier transform spectroscopy of SO in the X3Σ− and a1Δ electronic states

Abstract The v = 1 ← 0 vibration-rotation absorption bands of 32 S 16 O, 34 S 16 O, and 32 S 18 O in the ground electronic state, X 3 Σ − , and the v = 1 ← 0 vibration-rotation band of 32 S 16 O in the first excited electronic state, a 1 Δ, were measured at 0.004 cm −1 unapodized resolution with a high-resolution Fourier transform spectrometer coupled to a long path absorption cell. The v = 2 ← 0 vibration-rotation band of 32 S 16 O in the X 3 Σ − state was also observed. Line positions for P - and R -branch transitions up to N = 44 for 32 S 16 O have been measured and analyzed yielding improved molecular parameters. The present measurements are compared with previous infrared and microwave measurements.

The far infrared spectrum of magnesium hydride

The rotational spectrum of MgH in its ground 2∑ state has been observed for the first time using a new tunable far infrared spectrometer. The molecular constants derived are of sufficient accuracy to permit astrophysical identification of this species.

Laser magnetic resonance measurement of rotational transitions in the metastable a1Δg state of oxygen

Abstract Laser magnetic resonance (LMR) for five rotational transitions, J = 4 ← 3, 5 ← 4, 7 ← 6, 8 ← 7, 9 ← 8, of the oxygen molecule 16 O 16 O in its metastable state, a 1 Δ g , v = 0, are observed using six fir laser lines. Taking the known values of the g factors, their zero-field frequencies are obtained as 340.0085(6), 424.9810(9), 594.870(1), 679.780(1), and 764.658(1) GHz, respectively. They are fit by ( E h ) = B 0 [J(J + 1) − 4] + D 0 [J(J + 1) − 4] 2 + (−1) J ( 1 2 )qJ (J + 1)[J(J + 1) − 2] , where B 0 = 42.50457(10) GHz, D 0 = 153.14(110) kHz, and q = 0.050(90) kHz.

X‐band ESR spectrum of nitrogen dioxide

The ESR spectrum of gaseous NO2 has been studied experimentally over the pressure range 0.05–10 torr at X band for a range of polarizing magnetic field 1.5–8 kG. The spectra are interpreted by a theory which includes the effects of anisotropic electronic and molecular magnetism, intermediate coupling of angular momenta, and centrifugal distortion. Well isolated spectral lines at high magnetic field have been employed to give quantitative information on the electronic g tensor.

Microwave absorption lines of 16O18O in its (X3Σg−, v = 0) state

Abstract The microwave spectrum of 16 O 18 O in the X 3 Σ g − ground state is observed in the 50–400 GHz region. The rotational and centrifugal distortion constants and the spin-rotation and spin-spin interaction constants with their centrifugal distortion terms are determined. The obtained constants are consistent with those predicted by the theory of the isotope effect of O 2 (Mizushima, Jpn. J. Appl. Phys. 26 , 645–648 (1987)).

Velocity distribution in spectral line shape

Abstract In the derivation of the conventional Voigt profile formula, the width parameter of the Lorentz line shape formula is assumed to be independent of the velocity of radiating atoms. This assumption is acceptable when the pressure broadening is negligibly small in comparison with the natural broadening. When pressure broadening is more important than the natural broadening, however, the conventional Voigt profile formula is not valid since the width parameter depends appreciably on the velocity. The resulting profile is shown to yield about 30 per cent lower intensity than the Voigt profile in the tail region. Even when the Doppler effect is completely negligible (low-temperature limit), our profile deviates from the Lorentz profile, particularly in the tail region.

Strong‐Field Stark Effect of Asymmetric‐Top Rotator

A computer program is designed to calculate the Stark effect of lower rotational energy levels of an asymmetric top rotator with an arbitrary asymmetry parameter. Instead of using the perturbation expansion formula the program obtains eigenvalues of the secular equation with external electric field. With the available computer capacity, this means calculating up to about 10th order perturbation terms. The procedure is suitable and the only practical way to calculate Stark effect with strong field. Some results on the H2S and the SO2 molecules are shown.

Microwave Absorption Lines of 18O2 in its Electronic Ground State (X3Σ-g)

Microwave absorption lines of 18O2, in υ=0 and υ=1 states, are observed in the 119 and 60 GHz regions. Precisely determined molecular parameters for the 18O2 species are compared with those of 16O2 previously determined, and isotope dependences of the parameters are briefly discussed.