The infrared spectrum of methylenimine

Eleven isotopic species of methylenimine have been prepared by the mercury-arc photolysis of methyl azide isolated in argon, nitrogen, and carbon dioxide matrices at 4 and at 14 K. Sufficient concentrations of methylenimine were obtained for identification of all of the vibrational fundamentals except the NH stretching mode. Using a recent ab initio structural calculation for this molecule, it has been possible to derive a set of valence-force potential constants which provide a satisfactory fit to all of the infrared spectroscopic data. The magnitude of the carbon-nitrogen stretching force constant is appropriate for a double bond. The temperature dependence of the thermodynamic properties of methylenimine has also been calculated.     

The infrared spectrum of the CO dimer

The infrared spectrum of (¹²C¹⁸O)₂ has been studied for the first time using a tunable diode laser spectrometer in the 2095 cm⁻¹ region to probe a pulsed supersonic jet expansion. Very dilute gas mixtures of CO in He were used, resulting in small consumption of ¹²C¹⁸O sample gas, as well as cold and simple spectra. The results were analyzed using a term value scheme to obtain model-independent energies for 7 rotational levels belonging to 2 stacks in the lower state, v_CO=0, and 22 levels belonging to 7 stacks in the upper state, v_CO=1. The two ground state isomers of the CO dimer were found to be separated by only 0.639 cm⁻¹ for (¹²C¹⁸O)₂. These results provide a foundation for future studies of the millimeter wave spectrum.     

The infrared absorption spectrum of γ-phenylpyridine

The infrared absorption spectrum of-phenylpyridine has been recorded experimentally in the range 600–2000 cm^–1 and the fundamental frequencies and forms of the normal vibrations have been calculated using the valence force field. The experimental and calculated data show satisfactory agreement.In conclusion the authors wish to thank L. A. Gribov for assistance and discussion of the results.     

空间目标红外辐射特性研究

利用目标的红外光谱特性进行目标探测和识别是一种有效的方法。以空间卫星为目标,研究了其红外辐射特性形成的机理;利用所建立的数学模型,仿真了空间目标在探测面上所形成的红外光谱特性曲线;分析了模型中各参数对目标光谱特性的影响程度和卫星目标的红外光谱曲线。     

The high-resolution, jet-cooled infrared spectrum of pentafluoroethane

The jet-cooled spectrum of pentafluoroethane (C₂HF₅) has been recorded between 1100 and 1325 cm⁻¹ at a resolution of 0.0022 cm⁻¹. A rotational temperature of approximately 10 K was achieved by expanding 50 Torr of C₂HF₅ in 500 Torr of helium. Transitions belonging to five different fundamental vibrations have been assigned and fit to a Watson Hamiltonian: the ν₃ band at 1309.880494(189) cm⁻¹, ν₄ at 1200.734645(67) cm⁻¹, ν₅ at 1142.78147(33) cm⁻¹, ν₁₃ at 1223.334098(115) cm⁻¹, and ν₁₄ at 1147.394185(163) cm⁻¹. The fit of the ν₄ band has an rms deviation of 0.000436 cm⁻¹ compared to the uncertainty in the experimental line position of 0.0002 cm⁻¹. Satisfactory fits were achieved for the other four bands (ν₃, ν₅, ν₁₃, ν₁₄) at this cold temperature, with most of the centrifugal distortion constants fixed at the ground state values. Joint fits with previous work were attempted for the ν₄ and ν₁₃, successfully in the former case and unsuccessfully in the latter.     

The infrared spectrum of Cd3As2

We present new measurements of infrared reflectivity of Cd₃As₂ at 15 K. One plasmon and eleven phonon characteristics are determined by the fitting process that reveals weak dipolar moments in the structure.     

The ACE-FTS atlas of the infrared solar spectrum

The ACE-FTS is a space-borne Fourier transform spectrometer onboard SCISAT-1. The satellite was launched in August 2003 and since February 2004 the ACE-FTS has been performing solar occultation measurements in order to infer the chemical composition of the terrestrial atmosphere. The individual spectra recorded at the highest limb tangent altitudes (above 160 km) are by definition “high sun” spectra and contain no atmospheric contribution. In this work, an empirical solar spectrum covering the 700 to 4430 cm⁻¹ spectral range has been constructed from an average of 224,782 individual ACE-FTS solar spectra. Line assignments have been made for about 12,000 lines. The spectrum and two line lists are provided in the supplemental material attached to this work. Due to the excellent noise level achieved in the ACE-FTS solar atlas presented here, numerous weak absorption features are assigned which were not detectable in the ATMOS solar observations.     

氮化铝薄膜的红外吸收光谱和喇曼光谱的研究

本文报道用直流平面磁控溅射法在Si片上生长c轴高度择优取向AIN薄膜的光学特性.俄歇谱分析表明薄膜是高纯的.从红外吸收光谱上分析获得晶格振动纵、横模的频率分别为2.5×10~(13)HZ和1.8×10~(13)Hz.从喇曼光谱上分析获得AIN薄膜的光学声子频率为297、512、607、656、832cm~(-1).与几种已知的纤锌矿结构二元化合物的声子频率模式类比获得AIN的光学声子模式.进一步分析表明AIN是一种静电力大于原子间各向异性力的晶体,且声子的最高频率与r~(-3/2)N~(-1/2)成正比.     

Far infrared spectrum of methylamine

The far-infrared (FIR) spectrum of CH₃NH₂ has been studied in the 25–125 cm^–1 region at a resolution of 0.005 cm^–1 with a BOMEM Fourier transform spectrometer. All of the^rR branches with K rotational quantum number from 5 to 13 have been identified for A-a and E-a torsion-inversion symmetries in the ground torsional state, as well as some branches of A-s and E-s symmetries and some in excited torsional states. The observed branches have been fitted to series expansions in order to determine the branch origins.     

High-resolution infrared spectrum of cyanogen

The high-resolution spectrum of cyanogen (¹⁴N¹²C¹²C¹⁴N) has been measured from 500 to 4900 cm⁻¹. For this isotopomer many combination levels with both degenerate fundamentals, ν₄ and ν₅, have been measured for the first time and the effects of vibrational l-type resonance are observed as well as rotational l-type resonance. The effects of the vibrational resonance coupling ν₂ and 2ν₄ have also been studied. The data have been combined with earlier measurements below 500 cm⁻¹ to give a comprehensive catalog of the vibrational energy levels and the rovibrational constants for the normal isotopomer of cyanogen. A comparison of the term value constants for the three major symmetric isotopomers is given and they are compared with a recent ab initio calculation. The present data were combined with earlier work on the two symmetric isotopomers, ¹³C₂¹⁴N₂ and ¹²C₂¹⁵N₂, to obtain the equilibrium bond lengths, r_CC = 138.109(60) pm and r_CN = 115.976(40) pm.     

Far infrared spectrum of acrylonitrile

Two bands in the far infrared spectrum of acrylonitrile have been studied under moderately high resolution. Accurate band centers are obtained and the rotational constants are analyzed in terms of Coriolis coupling between the in-plane and out-of-plane bending modes.     

The near infrared cavity-enhanced absorption spectrum of methyl cyanide

The absorption spectrum of methyl cyanide (CH₃CN) has been measured in the near IR between 6000 and 8000 cm^?1 with a resolution of 0.12 cm^?1 using Fourier transform incoherent broadband cavity-enhanced absorption spectroscopy. The spectrum contains several weakly perturbed spectral regions; potential vibrational combination bands contributing to the spectrum are outlined. Line positions and cross-sections of CH₃CN between 6814 and 7067 cm^?1 have been measured at high-resolution of 0.001 cm^?1 using diode laser based off-axis cavity-enhanced absorption spectroscopy. A total of 4630 new absorption lines of CH₃CN are identified in this region. A value for the self-broadening coefficient has determined to be (3.3±0.2)×10^?3 cm^?1 mbar^?1 for one isolated line at 7034.171 cm^?1. Several line series have been identified in these regions and an autocorrelation analysis performed with a view to aiding future assignments of the rotational-vibrational transitions.     

The visible and photographic infrared spectrum of osmium oxide

The emission spectrum of OsO has been photographed in the region 405–875 nm where many new bands have been observed. In favorable cases the ${}^{190}\text{OsO}{}^{192}\text{OsO}$ isotopic splittings have been resolved and aid in vibrational assignments. Three visible bands in the region 433–470 nm have been assigned as (1,0), (0,0), and (0,1) of a $\text{ΔΩ}\text{= 0}$ electronic transition. The (0,0) and (0,1) bands have been rotationally analyzed, yielding principal constants (cm^?1) for the visible system of ν₀ = 22 273.3, B′₀ = 0.3657, D′₀ = 2.8 × 10^?7, B″_e = 0.4023, D″_e = 3.2 × 10^?7, $\text{Δ}\text{G″(}\text{1}\text{2}\text{) = 780.7}$, and $\text{Δ}\text{G″(}\text{1}\text{2}\text{) = 884.9}$. A band at 825.4 nm has been found to be a $\text{ΔΩ}\text{= +1}$ (0,0) band with the same lower state as in the analyzed visible bands. Constants for the upper state of the ir system are ν₀ = 12 109.7, B′₀ = 0.3845, and D′₀ = 3.1 × 10^?7 cm^?1.     

Near infrared emission spectrum of HCN

To record the infrared emission of hot molecular gases an optimized emission apparatus for the Bruker IFS 120 HR high-resolution FT-IR spectrometer has been constructed. Using this apparatus the hot gas emission spectrum of HCN at 1420 K has been recorded in the wavenumber region of 6000-6800 cm⁻¹ with a resolution of 0.044 cm⁻¹. This work reports the analysis of 33 bands with 58 subbands (9200 line positions). Thirty-seven rovibronic states of HCN including at 12 603 cm⁻¹ have been characterized for the first time and for 25 other states it was possible to improve the existing spectroscopic constants substantially. The very dense emission spectrum with many overlapping features was analyzed with new spectrum analysis software implemented using the Mathematica^TM computer algebra system. Spectroscopic constants have now been determined for 220 HCN rovibronic states. For 102 states the rovibrational spectroscopic constants have been determined for the first time or improved substantially using emission spectra measured in Giessen.     

High resolution infrared spectrum of silane

The infrared absorption spectrum of SiH₄ in the 4200–4500 cm^?1 region has been recorded using a high resolution grille-spectrometer. Two bands have been observed and identified as 2ν₃ and ν₁ + ν₃. Some molecular constants have been calculated, using the formalism developed by Jacques Moret-Bailly.     

Near infrared emission spectrum of HCN

The emission spectrum of H¹³CN at 1370 K has been recorded with a hot gas high resolution FT-IR emission apparatus [1] in the wavenumber region of with a resolution of . This work reports the analysis of 50 subbands for the H¹³CN isotopologue of hydrogen cyanide in the 2ν₁ wavenumber region. 23 rovibronic states of H¹³CN including the rovibronic states at have been characterized for the first time and for seven other states it was possible to improve the existing spectroscopic constants substantially. The dense emission spectrum was analyzed with the spectrum analysis software SyMath™ implemented in the Mathematica™ computer algebra system [1].