Absolute Intensities of the Infrared Bands of Gaseous Acrylonitrile

Laboratory spectral data (peak positions and integrated band intensities) of the infrared bands of acrylonitrile (CH2CHCN) gas in the region 4000-220 cm-1 are presented. Even though CH2CHCN has not yet been identified in Titan's atmosphere, it is among the possible photochemical and cosmic irradiation products of CH4 + N2 chemistry in the atmosphere of Titan. Laboratory simulations of Titan's atmospheric chemistry also give CH2CHCN as a product species. The results of our evaluation of the infrared intensity data provide an upper limit of the stratospheric abundance of CH2CHCN. Copyright 1999 Academic Press.     

Accuracy in Calculating the Intensities of the Absorption Bands in IR Spectra by Direct Quantum-Chemical Methods

To obtain information on the accuracy of quantum-chemical computations of the integral intensities of the absorption bands in IR spectra, calculations were performed by the density functional and ab initio methods for a number of polyatomic molecules that include the atoms of halogens, sulfur, phosphorus, etc. The results are compared with quantitative experimental data. A sufficient scatter in the calculated and experimental values has been found, but statistical processing of the results by the bootstrap method has revealed a regular deviation that can be partially compensated for by the coordinate scaling method.     

Temperature Dependence of Integrated Intensities of Vibrational Bands in M2GeF6 IR-Absorption Spectra

The paper presents experimental results of studies on the temperature dependence of integrated intensities of vibrational bands corresponding to ₃(GeF ₆) in M₂GeF₆ IR-spectra. It is shown that unlike Na₂GeF₆, Rb₂GaF₆, and Cs₂GeF₆, where the dependence of intensity on temperature is monotonous, in the case of K₂GeF₆ there exist anomalous temperature ranges of 220-240 and 150-170 K, where the intensity of a band, corresponding to ₃(GeF^2- ₆) changes abruptly. The study of heat evaluation, heat capacity, unit cell parameters, and intensities of selective reflexes in K₂GeF₆ X-ray diffraction patterns indicates the presence in this compound, as distinguished from others in the seris considerod, of phase transitions of the first order. On the basis of IB, ¹⁹F NNR, X-rat and calorimetric data, a possible mechanism of polymorphic transformation is discussed.     

红外吸收光谱法研究等离子体甲烷裂解规律

基于光谱吸收原理提出了利用3 391 nm He-Ne激光光源的甲烷探测方法,分析了交、直流辉光放电等离子体中甲烷裂解转化的过程和规律.探测对象选取甲烷3 390 nm附近的ν3谱带,采用单波长、双通道差分吸收探测,消除了光源不稳定及光电器件漂移等因素造成的误差影响.理论和实验表明,该方法有效地提高了系统探测的灵敏度及稳定性.     

Comparison Between the Induced Changes in the Intensities of Mid and Near Infrared Absorption Bands of Poly[Vinyl Alcohol] Due to Temperature and Solvents

The temperature induced changes in the intensities of the infrared absorption bands of PVA in both MID and NIR regions are presented. The absorption band at 1141cm^-1 is the only band among the bands in the mid region which is markedly affected by temperature. This band is taken as a measure of crystallinity of PVA. PVA shows two phase transitions at 80c⁰ and 120c⁰. The absorbances of the 1940nm in the near region is also temperature sensititve. The temperature dependence of the other bands in either mid or near regions is very weak. The effect of non polar and polar solvents such as n-hexane, carbon tetrachloride, toluene, chloroform, methanol and acetone is discussed. Comparison between the solvent induced changes in the intensities of the bands in mid and near regions is carried out. The data demonstrate that the bands in the near region ( overtone and combinations) are more sensitive to solvents than the bands in the mid regions. The combined effect of temperature and solvents on the intensities of absorption bands of PVA is also studied.     

质子交换铌酸锂光波导的红外吸收光谱

用尼高力 36 0型红外吸收光谱仪对用已二酸 (Adipicacid)和苯甲酸 (Benzoicacid)的不同摩尔比混合作为质子源进行质子交换制作的Z切铌酸锂光波导进行红外吸收光谱分析。表明 :OH-自由基团在 35 0 0cm-1处存在吸收峰 ,对应于质子交换中替代质子的特征 ,OH-氢键在 70 0cm-1处存在另一个吸收峰 ,对应于交换中的填充质子的特征。当两种不同的质子源以不同的摩尔比例混合时 ,质子源中的H 浓度不同 ,进行交换的速度也不同 ,结果导致在 35 0 0和 70 0cm-1两处的峰的强度发生变化。而这两个峰强度之比值可作为制作高质量铌酸锂光波导的重要依据 ,因此 ,对这两个峰的研究对制作高质量的铌酸锂光波导具有重要的意义     

基于QCL的红外吸收光谱技术的研究进展

量子级联激光器作为一种新型的单极型半导体激光器,其峰值发射波长处于中红外波段（2.5~25 μm）,具有功率高、线宽窄、响应速率快等传统半导体激光器所没有的独特优势,且具有较高的探测灵敏度,非常适合中红外波段的气体分子的检测。可广泛应用于大气痕量气体、呼吸气体、燃烧气体、生化气体、机动车尾气、工业废气以及农药残留气体等低浓度气体的检测。因此,利用量子级联激光器对气体分子进行探测在非侵入式医学诊断、环境监测以及工农业生产等领域都具有十分重要的意义。自20世纪末量子级联激光器发明以来,室温激光器的性能得到了长足的进步,也出现了多种结构形式的量子级联激光器。这也使得量子级联激光器红外吸收光谱技术得到了很大的发展。事实上,很多光谱技术在量子级联激光器发明之前就已经得到了发展和应用,而利用量子级联激光器作为光源则在很大程度上扩展了可探测波段,也在一定程度上提高了探测极限。这其中就包括了直接吸收光谱技术、波长调制技术、腔衰荡光谱技术、腔增强吸收光谱技术以及光声光谱等。综述了国内外量子级联激光器进行红外吸收光谱技术的研究现状和发展趋势,分析了量子级联激光器红外吸收光谱技术在发展过程中所遇到的瓶颈以及后期得到的解决方案,比较详细地介绍了各种方法的原理、应用,并指出了在吸收光谱测量中的优缺点,同时对外场痕量气体探测作了简要总结。最后,对量子级联激光器红外吸收光谱技术在未来痕量气体探测上的应用和发展进行了展望,指出随着红外吸收光谱技术的快速发展,这些方法可以得到更有效的改进和发展,进而朝着高灵敏度、高集成度以及高时效方向发展。     

基于红外技术的气体浓度检测方法研究

依据Lambert-Beer定律,推导出检测气体浓度的数学模型,得出了测量和参考探测器输出电压与气体浓度的函数表达式,表达式中的二个常数的数值取决于气室长度、气体吸收系数、探测器的电压探测率,经零点和满量程标准气样的标定,可确定这二个常数的数值,实现对仪器的标定.根据仪器零点随温度变化的关系,得到零点与温度函数表达式,用于零点温度补偿以及对零点温度补偿系数的计算;量程温度补偿方法是通过引入量程温度补偿因子,对测量和参考探测器输出电压与气体浓度的函数表达式进行修正,修正后的函数表达式用于量程温度补偿,也能对量程温度补偿因子中的补偿系数进行计算.矿用红外甲烷传感器采用本文的标定方法和温度补偿方法,在不同的环境温度下,对标准气样进行检测,其检测结果符合红外甲烷传感器标准所规定的基本误差.     

红外吸收光谱确定质子交换LiNbO3波导的深度

本文报道了利用红外光谱技术测量质子交换LiNbO3光波导浓度的一种新方法。该方法克服了传统的棱镜耦合技术＋IWKB方法只适用于多模波导不适用于单模波导缺点。实验结果表明该方法具有较好的准确性。     

红外吸收光谱确定质子交换LiNbO_3波导的深度

本文报道了利用红外光谱技术测量质子交换LiNbO3 光波导深度的一种新方法。该方法克服了传统的棱镜耦合技术 +IWKB方法只适用于多模波导不适用于单模波导缺点。实验结果表明该方法具有较好的准确性。     

中红外吸收光谱的气相过氧化氢浓度测量

气相过氧化氢为强氧化剂,其消毒、灭菌的最终产物为水和氧气,具有无残留、安全、快速消毒以及广泛的材料兼容性等优点.广泛应用于制药、医疗、卫生、生物安全等领域,特别是新冠肺炎、M ERS、S A RS以及甲流等呼吸类传染性疾病的消毒防治.为保证灭菌效果,防止无菌检查的假阴性或者假阳性,需要对过氧化氢的浓度进行监测.基于12...     

Comparative Investigation on the Concentration-Dependences of the Half-Band Widths of Infrared Absorption and Raman Bands

It is demonstrated that the fashions of the concentration-dependences of half-band widths are markedly different between the corresponding bands in i.r. absorption and Raman spectra when the i.r. absorption intensities of the bands are extremely large. On the other hand, when the i.r. intensities are not so great, the similar behaviour is observed for the changes in the half-band widths. In this study, these phenomena have been discussed in terms of the vibrational relaxation of resonance type and the local field effect.     

“Teflon”1 - A Matrix for Infrared Absorption Spectroscopy

It is a well-known observation in infrared absorption spectroscopy that certain bands of a spectrum when measured in solution differ considerably from the same bands obtained in solid state by the usual potassium bromide pellet technique². Since these solid phase spectra are critically affected by the preparation procedures of grinding, mixing, pressure, etc, solution spectra are routinely perferred due to their relatively good reproducibility.     

Calculations of the IR Intensities of Absorption Bands by the Hartree–Fock (ab initio) and Density-Functional Methods

Comparative calculations of the absolute intensities of bands in IR spectra were performed by the Hartree–Fock (ab initio) and density-functional methods for molecules containing different heteroatoms most cases, close coincidence between the curves calculated by these two methods is found, but there are also some unexpected disagreements in the results.     

甲烷红外吸收光谱原理与处理技术分析

由于工业监控和环境检测的需要,基于红外吸收光谱分析原理,研制甲烷传感系统,日益得到人们的关注。文章描绘了甲烷中红外的基频吸收带和近红外的ν₂+2ν₃组合带、2ν₃泛频带的吸收光谱强度分布,并给出了相应的吸收光谱曲线。定量数据表明,甲烷的基频吸收要比泛频吸收高两个数量级以上,较组合频吸收高3个数量级以上。文章还介绍了甲烷检测的差分技术、谐波技术、腔光谱增强技术、以及光声技术,给出了相应检测方法的理论公式、能够达到的检测灵敏度以及系统的结构。这些技术的有效性已经被研究报道所证明。     

金岛膜表面二硫双琥珀酰亚胺基丙酸酯分子吸附行为的表面增强红外光谱分析

二硫双琥珀酰亚胺基丙酸酯(dithiobis-succinimidyl propionate,DTSP)是一种重要的同源双功能偶联分子,广泛地应用于蛋白质在载体表面的共价固定。研究利用表面增强红外光谱分析了DTSP分子在真空蒸镀金岛膜表面的吸附特性。首先通过密度泛函理论对吸附于金表面的DTSP分子进行了结构优化,计算了该分子的振动模式和红外强度。表面增强红外吸收和变角偏振反射吸收测量结果表明TSP分子在金表面有序排列,其五元杂环平面与金表面法线成65°左右的二面角。此外,表面增强红外光谱还成功地监测到了TSP分子和Nα′,Nα″二(羧甲基)-L-赖氨酸在金表面的实时组装过程。     

银/二氧化硅复合材料对硝酸钠红外吸收光谱特性影响

对海洋营养盐进行快速检测是海洋污染监控中的一项重要任务。测量了硝酸钠溶液蒸发过程中的红外光谱,发现表面增强红外光谱法在营养盐的快速检测中有重要的应用价值。采用Stober方法制备了二氧化硅纳米颗粒,然后采用银氨溶液与二氧化硅溶液混合的方法制备银/二氧化硅(Ag/SiO₂)复合材料,并利用扫描电镜(SEM)、X射线衍射(XRD)以及紫外-可见(UV-Visible)吸收光谱对其进行表征。研究了硝酸钠水溶液干燥过程中Ag/SiO₂复合材料对硝酸钠红外吸收光谱的影响,结果表明硝酸根反对称伸缩振动吸收峰的吸收强度得到增强,这可能来自Ag/SiO₂薄膜材料的界面效应。     

镍岛膜上对巯基苯甲酸的表面增强红外吸收光谱研究

通过置换反应在金属铝表面制备了表面没有任何保护剂且具有红外增强作用的镍岛膜,用SEM、XRD和表面增强红外光谱对其形貌和性质进行表征。结果表明:铝片上沉积出的镍呈岛状结构,镍岛膜由大量的二次镍粒子和少量的一次镍粒子通过密堆积的方式构成;首次发现具有这种特殊结构的镍对吸附于其表面的有机分子的红外吸收光谱有较大的增强作用,使得表面增强红外光谱可以用于痕量分析、检测。     

CO2分子的近红外二极管激光吸收光谱灵敏探测

利用近红外二极管激光波长调制技术与二次谐波探测结合初步观测了CO2 分子在波长 1.5 7μm附近的吸收 ,获得了最小可探测吸收为 8.6× 10 -5(信噪比为 2 ) ,对应 5 0 0× 10 -6m-1的探测灵敏度。     

N_2O的近红外腔增强吸收光谱技术研究

以外腔式可调谐、窄线宽近红外半导体激光为光源,以一对曲率半径r=1 000mm的宽带高反射率平凹镜(反射率R=99.97%)构成的腔长为650mm的对称高精度光学稳定腔,建立了腔增强吸收光谱系统。详细研究了纯净N2O气体、以及N2O和N2的混合气体在不同浓度和不同气压下、中心波长位于6 561.39cm-1的腔增强吸收光谱、光谱强度和谱线宽度,该腔增强吸收光谱系统的有效吸收光程可达1 460km。获得了光谱线宽与气体压强的关系曲线,导出了波数6 561.39cm-1处N2对N2O的压力展宽系数为(0.114±0.004)cm-1·atm-1。采用该腔增强吸收光谱系统,开展了N2O气体检测研究,建立可用于定量检测的N2O气体腔增强吸收光谱强度与气体浓度关系曲线,获得了2.34×10-7cm-1的检测灵敏度,多次重复测量的相对标准偏差(RSD)为1.73%,在微量N2O气体检测中具有很好的应用前景。