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利用单模连续的钛宝石激光器, 构建了一台光腔衰荡光谱仪, 其可探测的最小吸收可达1.8×10-10/cm. 该光谱仪被用来记录C2H2分子在12240~12350 cm-1的泛频光谱. 与在同一波段测量的已报到的CRDS和激光腔内吸收光谱仪结果比较,本测量同时具有更好的灵敏度和精度. 由此,获得了乙炔分子在12290.12、12311.82和12350.61 cm-1附近高泛频谱带更准确的振转参数 相似文献
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本文报道了一个简化的利用可见光和红外光带宽来计算和频光谱分辨率的公式. 公式显示和频振动光谱的Voigt线宽可以通过振动模式的均匀线宽(洛伦兹线宽)、非均匀线宽(高斯线宽)、红外光与可见光的高斯线宽计算获得. 利用本实验室新搭建的频率分辨及偏振分辨的皮秒和频光谱系统验证了该公式的准确性. 实验结果显示,本激光系统获取的红外光的高斯线宽为1.5 cm-1. 本激光系统的光谱分辨率约为4.6 cm-1,结果与胆固醇单层膜光谱获取的光谱分辨率(3.5~5 cm-1)基本一致. 相似文献
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采用傅里叶变换红外光谱仪记录了富含15N216O同位素的一氧化二氮样品在1650-3450 cm-1波段的高分辨振转光谱,得到了该同位素分子超过7300吸收谱线位置的实验值,经分析实验精确度好于5.0×10-4 cm-1. 基于有效哈密顿量模型预测和带带转动分析,确定了所有吸收线的归属;获得了29个新吸收带的振转光谱参数,并优化了其他44个吸收带的光谱参数值. 并且发现有效哈 相似文献
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本文利用傅里叶变换离子回旋质谱仪和红外光学参量振荡器激光器相结合,在2700∽3700 cm-1范围内获得了由脯氨酸和苯丙氨酸组成的质子化异源二聚体ProPheH+的红外多质子解离(IRMPD)光谱. 实验光谱表明,ProPheH+除了在3565 cm-1处有一个对应于自由羧基O$-$H拉伸振动的吸收峰之外,在2935 cm-1和3195 cm-1处有两个宽吸收峰. 进一步对ProPheH+的结构在M062X/6-311++G(d,p)水平上进行了广泛的理论计算. 结果表明,其能量最稳定的构型具有电荷溶剂化结构,其中质子与脯氨酸单元结合. 这一构型的理论预测光谱与实验谱吻合较好. 相似文献
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本文利用微波相位法和光谱诊断法, 研究了ICP放电等离子体在圆台状夹层等离子体中E模和H模相互转换的物理现象. E模和H模的之间转换过程是一个瞬间突变的, 转换点的输入功率随真空室压强的变化而变化. H模向E模转换的阈值功率低于E模向H模转换的值, 等离子体参数随输入功率变化曲线类似于铁磁物质中的磁滞回线. Ar II 408.2 nm谱线的强度的变化规律和电子密度随功率变化的规律基本一致. 通过本实验可以获得一种电子密度范围为3.85×1011 cm-3 < ne < 4.68× 1011 cm-3, 外表面积为0.3 m2, 厚度为2 cm稳定工作的等离子体源. 相似文献
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以超低膨胀系数微晶玻璃为腔体,以分布反馈式激光器为光源,建立了一套等噪声测量灵敏度为3.2×10-9 cm-1的调腔式连续波腔衰荡光谱系统。应用该系统对1.517 μm附近(6 586.5~6 596.5 cm-1范围内)的7条水汽吸收谱线进行了实验研究,测得了这些谱线在氮气、空气环境下的谱线加宽系数。根据测得的结果,得到了此波段水汽的空气加宽系数与氮气加宽系数之比为0.896 9±0.068 7(3倍标准误差范围内),并就测得水汽的谱线加宽系数与HITRAN2004数据库数据进行了比较。 相似文献
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Using a diode laser spectrometer, we have studied with a great accuracy the N2-broadening coefficients in the ν4 band of methane. The experiments were performed at room temperature for lines in the P- and R-branches. We have measured 39 lines in the spectral range 1237–1373 cm−1 with J values between 1 and 12. Each line under study was recorded at four different nitrogen pressures, ranging from 20 to 91 mbar. The collisional half-widths were obtained by fitting individually a theoretical profile on the experimental profile of each line at each N2-pressure. We fitted the usual Voigt profile, but also the Rautian and Galatry lineshape models which take into account the collisional narrowing due to the molecular confinement (Dicke effect). The Rautian and Galatry fits are always better adjusted on the experimental profiles. For some lines, when the overlapping could not be disregarded, a fit of the blended profiles was performed using the same lineshape models. The collisional broadening coefficients obtained with Galatry and Rautian models are nearly equal and always higher than those derived from Voigt profile. Finally, we compare our results with previous determinations realized for several absorption bands. 相似文献
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A. Z. Nowakowski R. B. Dennis T. Scragg F. H. Hamza S. D. Smith 《Optics & Laser Technology》1976,8(3):133-136
Double beam optical techniques which allow direct spectroscopic measurements using both pulsed and cw tunable spin-flip Raman lasers have been developed. The systems provide a high resolution spectrometer (spectral linewidths 0.03 cm-1 pulsed and 0.003 cm-1 cw) in the range 5.3–6μm. Line frequency measurements are accurate to 0.01 cm-1 and intensity measurements to a few percent. Results of molecular spectroscopy provide a comparison of the relative performance of each system. 相似文献
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Yu. N. Ponomarev I. V. Ptashnik V. Zeninari B. Parvitte D. Courtois G. Durry 《Optics and Spectroscopy》2006,100(5):682-688
The absorption line profiles of water vapor in binary mixtures with diatomic molecules H2, N2, and O2 have been recorded on a diode laser spectrometer. The profiles of several lines of the 101 band have been studied near 1.39 μm with a spectral resolution of 3 × 10?4 cm?1. The pressure of the binary mixtures was varied from 0 to 200 Torr. The experimental data obtained have been used to test the Voigt, Rautian-Sobel’man, and Galatry theoretical models of a spectral line profile. The coefficients of collisional narrowing have been determined from the results of the fitting. 相似文献
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A. Foltynowicz P. Masłowski A. J. Fleisher B. J. Bjork J. Ye 《Applied physics. B, Lasers and optics》2013,110(2):163-175
We demonstrate the first cavity-enhanced optical frequency comb spectroscopy in the mid-infrared wavelength region and report the sensitive real-time trace detection of hydrogen peroxide in the presence of a large amount of water. The experimental apparatus is based on a mid-infrared optical parametric oscillator synchronously pumped by a high-power Yb:fiber laser, a high-finesse broadband cavity, and a fast-scanning Fourier transform spectrometer with autobalancing detection. The comb spectrum with a bandwidth of 200 nm centered around 3.76 μm is simultaneously coupled to the cavity and both degrees of freedom of the comb, i.e. the repetition rate and carrier envelope offset frequency, are locked to the cavity to ensure stable transmission. The autobalancing detection scheme reduces the intensity noise by a factor of 300, and a sensitivity of 5.4×10?9 cm?1?Hz?1/2 with a resolution of 800 MHz is achieved (corresponding to 6.9×10?11 cm?1?Hz?1/2 per spectral element for 6000 resolved elements). This yields a noise equivalent detection limit for hydrogen peroxide of 8 parts-per-billion (ppb); in the presence of 2.8 % of water the detection limit is 130 ppb. Spectra of acetylene, methane, and nitrous oxide at atmospheric pressure are also presented, and a line-shape model is developed to simulate the experimental data. 相似文献
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Ar-broadening coefficients have been measured in the P- and R-branches of the ν5 fundamental band of C2H2 for 30 lines at room temperature and 8 lines at −100 °C, using a tunable diode-laser spectrometer. These lines with J values ranging from 2 to 27 are located in the spectral range 665-795 cm−1. The collisional widths are obtained by fitting each absorption line with three lineshape models: the Voigt profile, the Rautian profile accounting for the Dicke narrowing effect, and a general Rautian profile including the absorber speed-dependent collisional broadening. The latter model provides significantly larger broadening coefficients than the Voigt model. These coefficients are also calculated from a semiclassical theory performed by using a simple intermolecular potential with two adjustable parameters. Finally, the temperature dependence of the broadening coefficients has been determined both experimentally and theoretically. 相似文献
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The vibrational–rotational absorption spectrum of D2O in the range from 10 120 to 10 450 cm–1 is recorded on a Fourier transform spectrometer with a resolution of 0.05 cm–1. The measurements were performed using a multipass White cell with an optical path length of 24 m. A light-emitting diode with brightness higher than that of other devices was used as a radiation source. The signal-to-noise ratio was about 104. The spectrum is interpreted as consisting of lines of more than 400 transitions. The spectral characteristics of lines (centers, intensities, and half widths) are determined by fitting the Voigt profile parameters to experimental data by the least-squares method. The intensities of lines and the experimental rotational energy levels of the (301) vibrational state of the D2 16O molecule with high rotational quantum numbers are determined for the first time. 相似文献
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2 laser standards. Using this technique, we can tune the CO laser frequency with absolute frequency control within the gain
profile of each laser transition. The frequency uncertainty is smaller than 15 kHz, corresponding to Δν/ν=2.5×10-10. Moreover, we obtain a reduction of the CO laser linewidth by a factor of 2 down to 65 kHz, corresponding to a spectral resolution
of δν/ν=1×10-9. With this outstanding accuracy and resolution we studied the shape of saturation dips in rovibrational lines of CO and carbonyl
sulfide (OCS) at low pressure (<5 Pa). The self-pressure-broadening rate of CO was found to be γc=+83(7) kHz/Pa in this pressure region. This value is about four times higher than values resulting from previous measurements
at much higher pressures. To our knowledge the measurements described here are the first line-shape studies with sub-Doppler
resolution in the 5 μm spectral region.
Received: 4 November 1996 相似文献
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Jean-Marcel Colmont Linh Nguyen François Rohart 《Journal of Molecular Spectroscopy》2007,246(1):86-97
Collisional relaxation has been considered for millimeter lines of carbon monoxide at room temperature. Accurate measurements of carbon dioxide- and rare gases-broadened widths have been performed on the J = 3 ← 2 rotational line of 12CO by using a video-type spectrometer. Measurements of nitrogen-, oxygen-, and xenon-broadened widths of the J = 5 ← 4 rotational line of 13CO were also carried by using a frequency-modulated spectrometer. A lineshape study performed on all the investigated binary systems provide confirmation that Voigt profile is not a suitable model to analyse experimental lines in the millimeter-waves region. On one hand, using this profile in the low pressure range, i.e. in the Doppler regime, the retrieved collisional linewidths do not follow a linear variation with the perturbing gas pressure. On the other hand, regardless of the pressure, lineshapes exhibit a narrowed profile. An accurate analysis of the pressure dependence of relaxation rates show that the Galatry profile is not appropriate and that experimental lineshapes are actually Speed Dependent Voigt profiles. Accurate broadening parameters were retrieved from this profile and compared to previous reported values and predictions calculated from the Robert-Bonamy formalism. Finally a variation of the ratio of relaxation speed dependence to broadening parameters versus relative masses of the collision partners is presented. 相似文献
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A. A. Solodov T. M. Petrova Yu. N. Ponomarev A. M. Solodov A. F. Danilyuk 《Molecular physics》2019,117(1):67-70
The absorption spectra of carbon monoxide confined in three aerogel samples with different pore sizes have been recorded within the 4100–4400?cm-1 spectral region at room temperature. The measurements were made using a Bruker IFS 125HR Fourier-transform infrared spectrometer. Lineshift and half-width values for CO were obtained. The influence of pore sizes on dependence of CO line half-width values on rotational quantum numbers was studied. 相似文献
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Characterization of 4Hben SiC substrates and epilayers by Fourier transform infrared reflectance spectroscopy
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Dong Lin Sun Guo-Sheng Zheng Liu Liu Xing-Fang Zhang Feng Yan Guo-Guo Zhao Wan-Shun Wang Lei Li Xi-Guang Wang Zhan-Guo 《中国物理 B》2012,21(4):47802-047802
The infrared reflectance spectra of both 4H-SiC substrates and epilayers are measured in a wave number range from 400 cm-1 to 4000 cm-1 using a Fourier-transform spectrometer. The thicknesses of the 4H-SiC epilayers and the electrical properties, including the free-carrier concentrations and the mobilities of both the 4H-SiC substrates and the epilayers, are characterized through full line-shape fitting analyses. The correlations of the theoretical spectral profiles with the 4H-SiC electrical properties in the 30 cm-1-4000 cm-1 and 400 cm-1-4000 cm-1 spectral regions are established by introducing a parameter defined as error quadratic sum. It is indicated that their correlations become stronger at a higher carrier concentration and in a wider spectral region (30 cm-1-4000 cm-1). These results suggest that the infrared reflectance technique can be used to accurately determine the thicknesses of the epilayers and the carrier concentrations, and the mobilities of both lightly and heavily doped 4H-SiC wafers. 相似文献