The infrared spectrum of diazirine: . Rovibrational analysis of the ν3 fundamental

Diazirine is one of the seven possible isomers of diazomethane. The medium-resolution infrared spectrum of this cyclic compound, which seems to be very stable in the gas phase, was reported by Ettinger. The mid-infrared spectra of diazirine and of the substituted isotopic species D₂CN₂, H₂¹³CN₂, and H₂C¹⁵N₂ were recorded with a resolution of 0.08 cm^?1. The overall assignment of these spectra is reported here. The ν₃ fundamental of the main species at 1459.15 cm^?1 (CH₂ deformation) is an A-type parallel band but presents a complicated band structure since diazirine is an asymmetric rotor with κ = ?0.427. The rovibrational assignment and the analysis of this band, together with the determination of the molecular constants, is given.     

The ν2 band of 14NH3: A calibration standard with better than 1 × 10−4 cm−1 precision

The Fourier transform spectra and the diode laser spectra of the ν₂ band of ¹⁴NH₃ have been measured with 0.005 and 0.002 cm^?1 resolution, respectively. A simultaneous least squares analysis has been carried out of these data together with the microwave, submillimeterwave, diode-laser heterodyne, and infrared-microwave two-photon transition frequencies between the ground and the ν₂ inversion-rotation levels. A theory of the Δk = ±3n interactions in the ground and ν₂ excited states of ammonia (?. Urban, V. ?pirko, D. Papou?ek, J. Kauppinen, S.P. Belov, L. I. Gershtein, and A. F. Krupnov, J. Mol. Spectrosc.84, 288–304 (1981)) has been used in the analysis. The “smoothed” values of the ν₂ band wavenumbers can be used for calibration purposes with better than 1 × 10^?4 cm^?1 precision. On the basis of these results, a critical evaluation has been carried out of several experimental techniques of very high resolution infrared spectroscopy.     

The A Matrix in Molecular Vibration-Rotation Theory

Crawford's A matrix in the theory of molecular vibrations is, in a sense, the inverse of Wilson's B matrix, but is not unique because B is rectangular. We consider the general form of A and then use the Eckart conditions to obtain the solution A = M(-1)B(T)G(-1), which has been widely used. Although the internal-coordinate harmonic force constants f = A(T)F(X)A, where F(X) are the Cartesian force constants, are superficially isotope-dependent, we show that this dependence vanishes. More generally, solutions of the form A = WB(T)(BWB(T))(-1), where W is an arbitrary nonsingular square matrix, are shown to give an f matrix that is independent of W. Copyright 2001 Academic Press.     

Doppler-free two-photon millimeter wave transitions in OCS and CHF3

Doppler-free two-photon rotational transitions J = 13<--<--11 and J = 12<--<--10 of OCS and J = 8<--<--6 and J = 7<--<--5 of CHF (3) were detected in the frequency range 134-156 GHz, using a novel, highly sensitive intracavity-jet technique. The sub-Doppler narrowing of the observed peaks (down to 40 kHz full width at half maximum as compared to 300 kHz of the Doppler width) demonstrates the potential of this new technique for high precision millimeter wave spectroscopy. The possibilities of the further reduction of the two-photon absorption line widths are considered.     

The Millimeter- and Submillimeter-Wave Spectrum of HC(3)N in the Ground and Vibrationally Excited States

The pure rotational spectrum of the astrophysically very important linear molecule cyanoacetylene, HC(3)N, in the ground and vibrationally excited states has been studied in selected regions from 118 to 814 GHz using the Cologne terahertz spectrometer. Vibrational satellites appendant to the following vibrational states have been recorded and analyzed (v(4), v(5), v(6), v(7)): (0, 0, 0, 1), (0, 0, 0, 2), (0, 0, 1, 0), (0, 0, 1, 1), (1, 0, 0, 0), (1, 0, 0, 1), and the Fermi resonance systems (0, 1, 0, 0)/(0, 0, 0, 3) and (1, 0, 0, 2)/(0, 2, 0, 0)(0e). With the exception of the latter resonance system, all states have been fitted within experimental accuracy. This work provides improved rest frequencies for the astronomical community and may also be beneficial in the improvement of global fits. Copyright 2000 Academic Press.     

The 3nu(2) Band of D(2)(16)O

The 3nu(2) overtone band of deuterium oxide, D(2)O, centered at 3474.3193 cm(-1), has been measured with high resolution in a 4-m base-length White cell attached to a Fourier transform spectrometer. The analysis of the spectrum led to the assignment of 347 transitions in this band, defining rovibrational energy levels in the (030) state up to K(a) = 7 for J as high as 9, and lower K(a) levels for J as high as 16. The (030) state was treated as an isolated state, following a Padé-Borel approximation in the effective Hamiltonian. Of the 115 energy levels included in the analysis, 80% were reproduced by the 21 adjusted parameters to within 0.0008 cm(-1), and the largest error was 0.0017 cm(-1). Copyright 2000 Academic Press.     

单位圆内代数体函数的T半径

应用Ahlfors覆盖曲面的方法,在单位圆内构造了代数体函数的一个新的奇异半径(称为T半径),并应用无穷级的型函数推广了亚纯函数奇异方向的相关结论.     

An array of scarlet and grey booklets: 65 years of the Symposium on Molecular Spectroscopy

A history of the OSU International Symposium on Molecular Spectroscopy is presented with a broad brush, inspired by looking at the evolution of the program booklets of the meeting, and drawing upon a selection of abstracts, all of which are now accessible on-line, and on reminiscences. The important and enduring aspects of the meeting from the perspective of the author are identified, and a few of the changes traced. The essential contributions of the founders and successive official hosts of the meeting, Harald H. Nielsen, David Dennison, K. Narahari Rao, and Terry A. Miller are acknowledged.