氰基取代亚甲基自山基的氧气氧化:新颖Criegee中间体NCC(H)OO顺、反异构体的红外光谱探测（英文）

本文采用基质隔离红外光谱分别对15.0 K温度下的HC(N_2)CN/O_2/N_2和HCCNCO/O_2/N_2混合物(1/50/1000)的激光光解过程开展了实验研究.结果表明:两者在紫外激光光照下均可产生Criegee中间体NCC(H)OO的顺、反两种构象异构体.对NCC(H)OO的红外光谱解析得到了氧同位素(~(18)O)标记实验和BP86/6-311++G(3df,3pd)理论计算结果的支持.实验发现NCC(H)OO在紫外光照下可进一步与氧气分子发生二次反应,生成氰基甲醛和臭氧,而未得到被理论所预测的能量较低的双环氧乙烷异构体cyclic-NCC(O_2)H.     

二(2-苯并咪唑亚甲基)胺合镝的合成及其与DNA作用的光谱研究

首次微波合成二（2-苯并咪唑亚甲基）胺（L）及其稀土金属镝的配合物[DyL2（NO3）2]NO3,用红外、元素分析、核磁共振、摩尔电导对其进行表征。用紫外可见光谱、荧光光谱、粘度研究了该配合物与鲑鱼精脱氧核糖核酸（DNA）的作用规律,结果表明：配合物以部分插入和静电作用模式与DNA键合。     

2,5-二(甲基苯基)-1,3,4-■二唑的红外光谱特性

本文用红外光谱法研究了２，５－二（邻甲基苯基）－１，３，４－二唑和２，５－二（间甲基苯基）－１，３，４－二唑的红外光谱特性，并对其主要谱带进行了指认和比较     

(7-甲氧基-4-亚甲基)香豆素基-单氮杂18-冠-6的合成及其离子识别功能(Ⅰ)——合成及光谱性质

合成、鉴定了题示光敏离子载体（ＭＭＣ－ＭＡＣ（Ｏ５ ））。基于不同ｐＨ值水溶液中吸收和荧光光谱的变化, 计算得该试剂基态和激发态分子的酸性常数（ｐＫａ ＝ ８．８４, ｐＫａ ＝ ５．１１）。基于在不同溶剂中荧光光谱的变化, 由Ｓｏｌｖａｃｈｒｏｍ ｉｃ法, 借助Ａｌｃｈｅｍ ｙ ２０００ 量化计算软件, 估算得该分子的基态和激发态偶极矩, 分别为３．１１Ｄ和８．１３Ｄ。同时发现, ＭＭＣ－ＭＡＣ（Ｏ５ ）水溶液除氧后其荧光强度奇迹般地提高近２０ 倍, 并伴随一定强度的延迟荧光发射。其荧光或延迟荧光强度与浓度在一定范围内呈良好线性关系。检测限分别为２×１０－ ９和１．３×１０－ ８ ｍ ｏｌ·Ｌ－ １ 。     

氘代最简单Criegee中间体CD2OO的振转光谱研究

本文采用振动自洽场/虚组态相关(VSCF/VCI)方法计算了氘代最简单Criegee中间体CD₂OO的振动和转动光谱. 计算得到的基频振动频率和转动常数与已有实验吻合. 这些数据可以用于未来该体系的光谱研究,特别是振动激发的转动常数对于实验光谱指认非常重要. 另外,不同来源的光谱强度,包括本文理论计算,文献中在NEVPT2和B3LYP水平上的计算结果以及实验结果,互相之间均不符合.     

Infrared Spectrum of Pyromellitic Diimide HN(CO)2C6H2(CO)2NH

The IR spectrum of pyromellitic diimide, HN(CO)₂C₆H₂(CO)₂NH, has been measured for polycrystalline sample. The observed bands have been assigned to the IR active fundamentals and combinations on the basis of a D_2h molecular symmetry by comparison with those of pyromellitic dianhydride. Band shifts from dianhydride to diimide were observed for the 0[dbnd]C-X-C[dbnd]O fundamentals and the N-H modes have been assigned by comparison with those reported for phthalimides.     

High-resolution FTIR measurement of the 2ν8 band of methylene fluoride (CH2F2)

A high-resolution (0.003 cm⁻¹) infrared absorption spectrum of the first overtone of the fundamental mode ν₈ of methylene fluoride (CH₂F₂) has been measured on a Bruker IFS 120-HR Fourier transform infrared spectrometer. More than 2000 ro-vibration transitions in the range of 2770-2900 cm⁻¹ with J ? 45 and K_a ? 20 have been assigned in this B-type band centered at 2838.5 cm⁻¹. Precise value for the band origin (2838.579799 cm⁻¹) and centrifugal distortion constants up to third order (Φ_JK, Φ_KJ, and Φ_K) have been obtained by fitting a total of 1474 unblended ro-vibration transitions (J ? 45 and K_a ? 13) of the 2ν₈ band with a standard deviation of 0.00029 cm⁻¹ using a Watson’s A-reduced Hamiltonian in the I^r representation. Signature of perturbations with nearby states has been seen.     

The initial interactions of beryllium with O2 and H2O vapor at elevated temperatures

In the 310-790 K temperature range, the mechanism of initial oxidation by O₂ is oxide island nucleation and growth. At the lower temperature range, oxygen is first chemisorbed and the oxide nucleates at coverage of ∼0.2. Increasing the temperature causes the oxide islands to nucleate at lower coverage and at 700 K and above, the oxide nucleates without any significant stage of chemisorbed oxygen. The temperature dependence shows that while the dissociation stage is not activated, the oxide nucleation and growth are thermally activated. Also, opposite to O₂ adsorption, the initial H₂O adsorption and oxidation rate was found to decrease with temperature. Opposite to the oxygen case, upon exposure to water vapor there is no noticeable stage of chemisorbed oxygen (or OH) and oxide is directly nucleated. Only after oxide coalescence, this tendency changes and the oxidation rate is increased with temperature.     

Infrared absorption of iodomethylperoxy (syn-ICH2OO) radical generated upon photolysis of CH2I2 and O2 in solid para-H2

Irradiation of a para-hydrogen (p-H₂) matrix containing diiodomethane (CH₂I₂) and O₂ at 3.2 K with light at 280 ± 20 nm, followed by annealing of the matrix at 4.0 K, yielded infrared (IR) absorption lines at 2982.4, 1408.9, 1231.8, 1226.5/1225.6, 1085.6, 917.7, 841.6/841.1, 550.5, and 490.2 cm^?1 that are assigned to the syn-iodomethylperoxy (syn-ICH₂OO) radical. Further irradiation of the matrix at 365 nm diminished these features. Experiments with CH₂I₂ and ¹⁸O₂ yielded lines of syn-ICH₂¹⁸O¹⁸O at 1407.3, 1228.1/1227.7, 1217.7/1217.0, 1031.5, 899.9/899.4, 836.7/836.0, and 473.6 cm^?1. The assignments are based on the photolytic behaviour and comparisons of observed vibrational wavenumbers, IR intensities, and ¹⁸O-isotopic shifts with those predicted with the B3LYP/aug-cc-pVTZ-pp method. The observation is consistent with a mechanism that, upon photolysis of CH₂I₂ at 280 nm, CH₂I was formed and subsequently reacted with O₂ to yield syn-ICH₂OO. Compared with the gaseous reaction CH₂I + O₂ → CH₂OO + I at low pressure, observation of ICH₂OO in a p-H₂ matrix instead of CH₂OO in the gaseous phase indicates that the excess energy of internally excited ICH₂OO, produced upon reaction of CH₂I + O₂, was rapidly quenched in the matrix so that ICH₂OO became readily stabilised without further decomposition to form CH₂OO + I.     

N2- and O2-broadening of CO2 for the (301)III ← (000) band at 6231 cm

The N₂- and O₂-broadening effect have been investigated for 10 absorption lines of the CO₂ (30⁰1)_III ← (00⁰0) band centered at 6231 cm⁻¹, in the range from P(28) to R(28) by a near-infrared diode-laser spectrometer. We have analyzed the observed line profiles with the Galatry function, and determined the N₂- and O₂-broadening coefficients precisely. The air-broadening coefficients for these lines have been derived. The present results are compared with those of the previous studies for this band and with some of the other bands.     

The reaction of hydroxyethyl radicals with O2: A theoretical analysis and experimental product study

Reactions of α-hydroxyethyl (CH₃CHOH) and β-hydroxyethyl (CH₂CH₂OH) radicals with oxygen are of key importance in ethanol combustion. High-level ab initio calculations of the potential energy surfaces of these two reactions were coupled with master equation methods to compute rate coefficients and product branching ratios for temperatures of 250-1000 K. The α-hydroxyethyl + O₂ reaction is controlled by the barrierless entrance channel and shows negligible pressure dependence; in contrast, the reaction of the β isomer displays pronounced pressure dependence. The high pressure limit rate coefficients of both reactions are about the same at the temperatures investigated. Products of the reactions were monitored experimentally at 4 Torr and 300-600 K using tunable synchrotron photoionization mass spectrometry. Hydroxyethyl radicals were produced from the reaction of ethanol with chlorine atoms and the β isomer was also selectively produced by the addition reaction C₂H₄ + OH → CH₂CH₂OH. Formaldehyde, acetaldehyde, vinyl alcohol and H₂O₂ products were detected, in qualitative agreement with the theoretical predictions.     

Infrared optical properties of Ba(Zr0.20Ti0.80)O3 and Ba(Zr0.30Ti0.70)O3 thin films prepared by sol-gel method

Ba(Zr_xTi_1−x)O₃ (BZT) (x = 0.20 and 0.30) thin films are deposited on Pt(1 1 1)/Ti/SiO₂/Si(1 0 0) substrate by sol-gel method. X-ray diffraction patterns show that the thin films have a good crystallinity. Optical properties of the films in the wavelength range of 2.5-12 μm are studied by infrared spectroscopic ellipsometry (IRSE). The optical constants of the BZT thin films are determined by fitting the IRSE data using a classical dispersion formula. As the wavelength increases, the refractive index decreases, while the extinction coefficients increase. The effective static ionic charges are derived, which are smaller than that in a purely ionic material for the BZT thin films.     

Inhibition of initial surface oxidation by strongly bound hydroxyl species and Cr segregation: H2O and O2 adsorption on Fe-17Cr

The initial stages of surface oxidation of Fe-17Cr (ferritic stainless steel) were investigated at 323 K by X-ray photoelectron spectroscopy (XPS) and inelastic electron background analysis. The results indicated the formation of a mixed iron-chromium oxide layer upon O₂ exposure and the formation of a thin chromium oxyhydroxide layer upon H₂O exposure. The oxidation of Fe did not occur in the latter case. Moreover, it was found that pre-exposing the Fe-17Cr surface to H₂O significantly hinders subsequent oxidation by O₂, thus providing a way to control the formation of nanoscale oxides on stainless steel materials. It was concluded that the formation of strongly bound hydroxyl species together with adsorbate-induced segregation of Cr severely limits the reaction between O₂/H₂O and Fe from the alloy.     

过渡金属羰基化合物Mn(CO)5Br和Re(CO)5Br结构与动力学的超快光谱

利用超快泵浦探测红外光谱、稳态线性红外光谱和计算化学方法,对过渡金属羰基化合物Mn(CO)₅Br和Re(CO)₅Br的振动和结构动力学进行了研究. 借助羰基的两个伸缩振动峰(处于低频的A₁模式和处于高频的简并E模式)进行了观测. 结果表明,在两个配合物中,A₁和E模式振动峰的振动频率位置及频率差都与中心金属原子对羰基的键级和振动力常数的影响相关. 而A₁模式比E模式的线宽宽一些,部分由于振动寿命的影响. 此外,从瞬态光谱中获得了振动模式依赖的对角非谐性常数,发现在两个羰基化合物中E模式的非谐性总是较小.