Harutoshi Takeo

Observation of the infrared spectra of the NH2-stretching vibration modes of anilineArn (n = 1, 2) clusters in a supersonic jet using REMPI

Abstract The infrared spectra of the NH2 stretching modes of anilinen (n = 1, 2) clusters and corresponding cluster cations in a supersonic jet have been observed using an IR-REMPI double resonance technique. The observed frequencies of the anilineue5f8Ar cluster are νsym = 3422, and νasym = 3508 cm−, and those of the aniline-Ar+ cation are νsym = 3395 and νasym = 3489 cm−. The frequency shifts of the NH2 stretching modes due to the Ar atoms have been found to be small. The aniline-Ar+ cluster ionized by the REMPI method has been found to be cold and the infrared spectrum shows not hot bands from the van der Waals modes, even though the excess energy above the ionization is as much as 5600 cm−1. A process which gives the cold clusters is discussed.

Microwave spectrum of aminoborane, BH2NH2

Abstract The unstable species aminoborane, BH2NH2, has been identified as a reaction product of ammonia with diborane by microwave spectroscopy. The rotational constants determined are A = 138212 ± 4 MHz, B = 27487.83 ± 0.10 MHz and C = 22878.44 ± 0.11 MHz for 11BH2NH2 and A = 138199 ± 6 MHz, B = 28420.36 ± 0.11 MHz and C = 23520.78 ± 0.12 MHz for 10BH2NH2. The dipole moment is 1.844 ± 0.015 D.

Microwave spectrum of formyl chloride

The unstable product found in the chlorination of formic acid has been identified as formyl chloride by microwave spectroscopy. The lifetime of this molecule was about 3 min in the waveguide cell at dry ice temperature. The rotational constants of seven isotopic species have been measured and analyzed, yielding moments of inertia from which a molecular structure was calculated. The bond lengths found are (in A)C–Cl=1.760, C–O=1.188, and C–H= 1.096. The bond angles are HCCl=109°58′ and HCO=126°29′. Planarity was established by the analysis of the inertia defects. The nuclear quadrupole coupling constants in the C–Cl bond‐axis system are χzz= −59.8 MHz and η=−0.30. From the analysis of the Stark effect under a weak electric field condition, the dipole moment has been determined as ‖μa‖=0.3±0.2 D, ‖μb‖=1.6±0.2 D, and ‖μtotal‖ = 1.6±0.2 D.

Microwave spectroscopic detection of BFHOH and BH(OH)2

Abstract Transient molecules, BFHOH and BH(OH) 2 , have been detected by microwave spectroscopy in the hydrolyses of diborane and BF 3 . Their conformations have been determined from the inertia defects and the differences in moments of inertia between normal and deuterated species.

Observation of infrared absorption spectra of molecular ions, H3+ and HN2+, by FTIR spectroscopy

Abstract The infrared absorption spectra of the molecular ions H 3 + and HN 2 + were measured by using the Fourier-transform infrared method and a hollow-cathode discharge cell. From the analysis of the relative intensities and the linewidths of the absorption lines, these ions in the ground vibrational states were found to be well thermalized in the cell. The band center of the v 1 mode of HN 2 + has been determined to be 3233.9608(2) cm −1 which is slightly higher than the literature value.

Structure of the aniline–benzene and aniline–cyclohexane clusters based on infrared depletion spectroscopy

Abstract The vibrational spectra of jet-cooled aniline–benzene and aniline–cyclohexane clusters have been investigated using infrared depletion spectroscopy combined with REMPI–TOF mass spectrometry. The symmetric and antisymmetric NH2 stretching bands are red-shifted by 28.4 and 40.9 cm−1 in aniline–benzene and by 1.6 and 1.2 cm−1 in aniline–cyclohexane, from those of the aniline monomer. The spectrum of aniline–benzene suggests a face-to-face structure with NH2–π hydrogen bonds. This structure is supported by ab initio calculations at the MP2 level, which also reproduce the observed red-shifts. The small red-shifts in aniline–cyclohexane indicate no direct interaction of the amino hydrogens with cyclohexane.

Observation of FTIR-PA spectra of langmuir-blodgett films of cadmium arachidate on glass plates

Abstract Infrared spectra of Langmuir-Blodgett films of cadmium arachidate on glass plates were measured using photoacoustic Fourier transform infrared spectroscopy (FTIR-PAS). A spectrum of a single monolayer could be measured with reasonable signal to noise ratio. The orientation of the hydrocarbon chain and a frequency shift of the CH 3 stretching vibration in one monolayer films are discussed. The FTIR-PAS method was found to be useful for observation of infrared spectra of LB films on substrate materials which strongly absorb infrared radiation.

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 ue5f8 A 2 splitting of the K = 3 level is found to be 20.4±3.8 MHz for J = 39.

Microwave spectrum of CIS chlorine nitrite, CIONO

Abstract The metastable intermediate product, CIONO, which is formed from gaseous CINO and Cl 2 O at about 203 K, has been detected by microwave spectroscopy. The rotational constants and the inertial defects for the 35 Cl and 37 Cl species establish that the observed spectrum is that of planar cis CIONO.