Michio Takami

Infrared diode laser spectroscopy of the ν2 band of BF3

Abstract The vibration-rotation spectra of the ν 2 , ν 2 + ν 4 − ν 4 , and 2 ν 2 − ν 2 bands for 10 BF 3 and 11 BF 3 , and the ν 1 + ν 2 − ν 1 band for 11 BF 3 have been measured by a tunable diode laser with Doppler-limited resolution (0.001 cm −1 ). The ν 2 + ν 4 − ν 4 band is found to be perturbed significantly by the l -resonance interactions in the ν 4 and ν 2 + ν 4 states. By analyzing this interaction explicitly the l -type doubling constants for the ν 4 state of 10 BF 3 and 11 BF 3 have been determined to be 0.000694(4) and 0.000670(3) cm −1 , respectively. The equilibrium B-F distance, 1.3070(1) A, and several cubic force constants have been obtained from the determined rotational constants.

High-resolution infrared spectrum of hydrazoic acid: The ν3 fundamental by a tunable diode laser

Abstract The HNN bending fundamental ν3 of HNNN, and a-type band, was measured by a tunable diode laser with Doppler limited resolution. The Stark modulation technique was used to confirm the assignment. The assignment of Q branches was revised, and the origins, effective B and D values for each subband, were determined accurately. The K dependence of these subband origin parameters, B and D, was found quite anomalous. Possible interactions are discussed.

Infrared-microwave double resonance of propynal by using the 3.51 μm HeXe laser

Abstract The 3.51 μm HeXe laser is magnetically tuned over a wavenumber of 0.2 cm −1 and used for infrared absorption and double resonance spectroscopy. Eight rotation-vibration lines of propynal in the ν 2 band are assigned by the Stark effect. Eleven microwave transitions in the v 2 = 1 vibrational state are observed by the method of infrared-microwave double resonance. The rotational constants of the excited state and the band origin of the vibration ν 2 are determined from the observed spectra.

Pure rotational transitions in the ground vibrational state of 10BF3 observed by infrared-crowave double resonance

Abstract Rotational transitions of 10 BF 3 due to the centrifugal distortion-induced dipole moment in the ground vibrational state have been observed by infrared-microwave double resonance using a tunable diode laser. The axial rotational constant. C 0 , is determined to be 5161.40±0.05 MHz. The A 1  A 2 splitting of the K = 3 level is found to be 20.4±3.8 MHz for J = 39.

Microwave spectroscopy of propynal in the v2 = 1 vibrational state by IR-MW triple resonance

Abstract Infrared-microwave triple resonance was applied to microwave spectroscopy of propynal, HCCCHO, in the v 2 = 1 vibrational state. Eleven microwave transitions were newly observed by using a Zeeman-tuned 3.51 μm HeXe laser as the infrared radiation source. The spectrum was analyzed including the 11 transitions previously observed by double resonance. A least-squares fit of the 13 low- J transitions revealed that the rotational constants in the K −1 = 1 states were slightly different from those of the K −1 = 0 states. A higher-order rotational resonance was proposed for explanation of the effect.

Infrared multiple-photon decomposition of Fe(CO)5 induced by an infrared p-H2 raman laser

Abstract Infrared multiple-photon decomposition (IRMPD) of Fe(CO)5 induced by an IR p-H2 Raman laser has been studied. The decomposition efficiently occurs with the irradiation of unfocused laser beam at 616.2 cm−1. The decomposition products are mainly CO and metallic iron. In IRMPD of a mixture of Fe(CO)5 and 1-butene or 1-pentene, isomerization of these olefins by active intermediates is not observed. The results are explained by fast sequential decarbonylation of Fe(CO)5 in highly excited vibrational states.

Millimeter-wave spectrum of DCCCHO in the ground vibrational state

About 140 a- and b-type millimeter-wave transitions of propynal-d1, DCCCHO, were measured in the ground vibrational state. The accurate rotational and centrifugal distortion constants were determined from the observed frequencies including the previous microwave measurements. Seven microwave transitions observed by infrared-microwave double resonance were also included in the analysis. The determined constants are A = 66778.016(12), B = 4463.8489(7), C = 4177.7950(7), ΔJ = 0.0015919(5), ΔJK = −0.139214(13), ΔK = 9.4328(18), δJ = 0.0002885(4), δK = 0.03069(4), HJK = −0.817(13) × 10−6, HKJ = −9.62(4) × 10−6, HK = 0.00255(8), hJ = 0.0047(3) × 10−6, in MHz.

Spectroscopy of microclusters in superfluid helium

The optical spectra of microclusters in superfluid helium (HeII) are studied by a dissociation/emission spectroscopy. The microclusters are produced by ablating solid samples immersed in Hell with a pulsed YAG laser. The absorption spectra are measured by dissociating the clusters with a pulsed dye laser and observing the recombination lines of atomic ions. Narrow excitation spectra observed in Ca and Sr are attributed to the absorption by the van der Waals clusters of these atoms.