自由基分子NH2ν2带CO激光磁共振π谱的观测

采用高灵敏度、高分辨率激光磁共振光谱(LMR)方法在6μm谱段测量了自由基分子NH₂ν₂带的π谱(ΔM_J=0).测量了前人已测过的谱,结果与之较好符合.并观测到了前人没有观测过的新谱,在3支激光谱线下共获得约13支塞曼(Zeeman)跃迁谱线,其中在2支激光谱线下新测得的谱线10支.利用我们已经测得的^[8]σ谱的新的共振谱线的数值和已取得的激光磁共振谱线的标识方法,可预期得到NH₂的一些新的分子参数.     

自由基分子NH2υ2带CO激光磁共振σ谱的观测

采用高灵敏度,高分辨率激光磁共振光谱(LMR)方法在6μm谱段测量了自由基分子NH₂υ₂带的σ谱(△M_J=±1)。重复了前人已测过的谱,结果与之较好符合。并观测到了新谱,在14支激光谱线下共获得约115支塞曼(Zeeman)跃迁谱线,其中在6支激光谱线下新测得的谱线91支。     

281—332nm SO+2的光碎片激发谱研究

在超声分子束条件下，利用380.85nm的电离激光使SO₂分子经由［３＋１］共 振增强多光 子电离(REMPI)制备纯净的分子离子SO⁺₂(²A ₁(000))，用另一束解离激光在281 —332nm扫描获得了光解碎片激发(PHOFEX)谱.获得的光碎片SO⁺激发谱基本可以 归属为SO ⁺₂(,)←SO⁺关键词： +₂')" href="#">SO⁺₂ 光解离 光碎片激发谱     

超声冷却SO2( 1A2— 1A1)激光诱导荧光激发谱的转动分析

通过改变SO₂/Ar配比，研究了超声膨胀冷却SO₂( ¹A₂— ¹A₁)系统315—330nm波段振动分辨的激光诱导荧光(LIF)激发谱.获得了属于两个完整带系(1,m,1),(0,n,1)—(0,0,0)的高分辨转动结构谱.其中(ν′₁,ν′₂,ν′₃)=(0,9,1),(0,10,1),(1,7,1),(1 关键词：     

C2H221分子转动角动量定向分布(Orientation)及其碰撞弛豫和转移

利用圆偏振激光受激Raman抽运,以 C₂H₂分子为样品选择性地制备了它的电子基态单一转动态(X¹Σ⁺_g,ν″₂＝1,J″的角动量定向布居(orientation)．并从圆偏振紫外激光诱导的A¹A_u(ν′₃＝1)←X¹Σ⁺_g(ν″₂＝1)的荧光（谱）,直接测定了 C₂H₂(X¹Σ^＋_g,ν″₂＝1,J″＝4,7,8,…,13）的角动量定向布居值．从时间分辨的荧光信号谱测定了角动量定向布居的碰撞弛豫速率常数,同时还研究了由各初始激励的转动态向其他邻近转动态碰撞诱导的角动量定向布居转移． 关键词：     

(Hf0.5Zr0.5V2)Hx的声子谱与超导性的关系

本文报道了用Be过滤探测器谱仪对C-15相的(Hf_0.5Zr_0.5V₂₎H_x等五种样品的声子谱的测量。观察到了它们的声子谱随含氢量而变化以及声学支有规则的软化现象。表明(Hf_0.5Zr_0.5V₂₎H_x的T_c随x的变化,主要是声学支的贡献,声学文软化有利于T_c的提高,而光学支“软化”可能会抑制超导性。 关键词：     

脉冲CO2激光器的多频动力学模型

建立了适用于各种气压下(20×133—20×10⁵ Pa)的脉冲CO₂激光器的六温度多频动力学模型，该模型考虑了增益谱线重叠效应，序列带、热带的影响，以及非洛伦兹线型效应.对模型进行数值求解可以预言和解释不同气压下的脉冲CO₂激光器的输出特性，有助于评价不同的抽运设计和研究可调谐特性，为设计脉冲CO₂激光系统提供理论支持. 关键词： 2激光器')" href="#">CO₂激光器 激光动力学 六温度模型 增益谱线重叠     

配合物PdCl2[(PPh2)2CHCl]的合成、结构及反应机理

合成了新配合物PdCl₂[(PPh₂)₂CHCl],用核磁、红外光谱、元素分析等表征了其结构,X-rax衍射确定了单晶结构.应用电子顺磁共振-自旋捕获(EPR-ST)对技术研究了其反应的机理.捕获到PPh₂及含碳自由基中间体,提出了反应机理.     

NO(X2∏1/2,3/2)v=1←0塞曼跃迁谱及其特性研究

根据塞曼效应理论和激光磁共振光谱技术(LMR)的基本原理,讨论了双原子分子²∏态的塞曼效应特性并导出了解释分子塞曼跃迁的简明代数拟合方程,用这些方程对¹⁴N¹⁶O(X²∏_1/2.3/2)及¹⁵N¹⁶O(X²∏_3/2)(v=1←0)的LMR谱线进行数据拟合,得到塞曼跃迁上、下子能级的g_J因子值和二级塞曼效应因子k₂.将按Hund耦合情形(a)及过渡情形(ab)的理论和拟合方程计算出的磁场位置分别与实验结果相比较,结果表明对NO分子而言,过渡情形(ab)能较真实反映它的耦合情况,且在较高强度磁场下,必须计及二级塞曼修正验证了采用上述代数拟合方程实现新分子LMR谱线标识和指认的可靠性,并提供了系统的处理方法.     

超声射流冷却CCl2自由基的激光诱导荧光激发谱

在497—517nm波长范围观测超声射流冷却CCl₂自由基的激光诱导荧光激发谱。得到CCl₂在?←X跃迁中(v₁,v₂,0)←(0,0,0)振动带清晰的K结构。对近80个子谱带作了归属。振动分析给出较精确的v＇₁和v＇₂振动频率和非谐性常数;从K结构的分析得出(A＇-B＇)和(A″-B″)的值,文献未曾报道过。 关键词：     

非晶锂离子导体B2O3-Li2O-LiCl一Al2O3中VO2+的电子自旋共振

两种非晶锂离子导体B₂O₃-0.7Li₂O-0.7LiCl-xAl₂O₃-0.1V₂O₅(x=0.05和0.15)的电子自旋共振谱研究表明:(i)ESR线型是高斯型,证实V₂O₅添加量适当;(ii)超精细结构来源于VO²⁺络离子,具有四角对称性,属C_4v群。越精细耦合张量的平行分量平均值A_//=0.0175cm^-1,垂直分量A_⊥=0.0063cm^-1。由g_//(g_⊥)求出其基态²B_2g与第一激发态²E_g的能级间距△₁=2.46×10⁴ cm^-1,基态与第二激发态²B_1g的能级间距△₂=3.03×10⁴ cm^-1;(iii)变温实验证实:Al₂O₃组分较少(x=0.05)的非晶ESR强度比x=0.15的非晶高3倍至2倍,而Al₂O₃组分越多则ESR强度随温升下降越小。     

Mo-SiO2-C3H6催化反应体系的ESR动态表征

文章考察了Mo-SiO₂催化剂体系在丙烯歧化反应过程中的动态ESR波谱,发现在催化歧化反应过程中有两种Mo⁵⁺顺磁中心,一种为扰动八面体配位,g_||=1.89,g_⊥=1.94;另一种为扰动四棱锥配位,g_||=1.86,g_⊥=1.95。测得同位素^95,97Mo⁵⁺的各向异性超精细耦合常数A_||=90.3×10^-4cm^-1,A_⊥=44.8×10^-4cm^-1;观测到反应产生的积炭信号,g≈2.0O₂;氧阴离子自由基信号g₁=2.018,g₂=2.011,g₃=2.005。用LCAO-MO理论对上述Mo⁵⁺的ESR波谱进行计算,求得分子轨道系数,发现并总结出△g_||/△g_⊥与△g成直线关系,并建议用△g_||/△g_⊥=4(△E(B₂→E))/(△E(B₂→B₁)(β₁/ε)²之比值作为衡量C_4v扰动程度的尺度。     

Structural deformation of nitro group of nitromethane molecule in liquid phase in an intense femtosecond laser field

The structural deformation of NO_2 group induced by an intense femtosecond laser field of liquid nitromethane(NM)molecule is detected by time-and frequency-resolved coherent anti-Stokes Raman spectroscopy(CARS) technique with the intense pump laser. Here, we present the mechanism of molecular alignment and deformation. The CARS spectra and its FFT spectra of liquid NM show that the NO_2 torsional mode couples with the CN symmetric stretching mode and that the NO_2 group undergoes ultrafast structural deformation with a relaxation time of 195 fs. The frequency of the NO_2 torsional mode in liquid NM(50.8±0.3 cm~(-1)) at room temperature is found. Our results prove the structural deformation of two groups in liquid NM molecule occur simultaneously in the intense laser field.     

XPS investigation on Upilex-S polyimide ablated by pulse TEA CO2 laser

Laser ablation of Upilex-S polyimide films 80 μm thick was performed in air using a pulse TEA CO₂ laser with wavelength 9.3 μm. A halo surrounding the hole was observed, which is covered with sub-micro particles. Pieces of ablation products protrude from the ablated surface, leading to considerable roughness of the ablated area. Chemical and structural changes of Upilex-S polyimide film surface irradiated by the pulse TEA CO₂ laser in air were analyzed by X-ray photoelectron spectroscopy (XPS). Relative C content in the ablated area was found to be higher, whilst both O and N contents were lower than in the untreated area. This means that TEA CO₂ laser ablation released both the O and N atoms. Also, the peak areas corresponding with carbonyl group (C=O) in the imide system were reduced much more and a new component at 287.0 eV assigned to the amide structure (N---C=O) was detected after laser ablation. These suggest that the pyrolysis of the Upilex-S polyimide was the decomposition of the imide ring between the nitrogen/aromatic carbon atom and carbonyl carbon atom. In addition, another new component arising from >C=O groups was also detected for higher fluence (7.83 J/cm²), and its peak areas is very small. This result indicates that the slight oxidation may take place with higher fluence during laser ablation in air. Based on above-mentioned experimental results, a possible thermally-induced decomposition path of Upilex-S polyimide ablated by TEA CO₂ laser is presented.     

Characterization and frequency measurement of a new far infrared laser line from CHin2Fin2

We present the discovery and frequency measurement of a new FIR laser line from CH₂F₂ optically pumped by a waveguide CO₂ laser. This new line has the same CO₂ laser pump line (9R32), offset (+5 MHz) and relative polarization of the strongest FIR laser line of CH₂F₂, namely the 184.3μm. The frequency is only 19,454 MHz apart from that of this line. We got a frequency measurement of 1,646,196.6 (10) MHz, which corresponds to a wavelength of 182.112 μm.     

酰胺化合物于金属修饰的TiO2粒子表面的光催化分解

用ESR方法研究了5种脂肪酰胺化合物在经金属银修饰后的二氧化钛微粒表面光诱导电子转移和有关光催化反应行为。结果发现经修饰过的与未修饰过的TiO₂粒子的光催化特性有极为明显的差别。当体系中无TiO₂存在时,只是甲酰胺有很微弱的反应,加合物(DMPO-CONH₂)·的信号被检出,而其它4种酰胺均无ESR信号。除碳中心自由基外,还有(DMPO-OH)·信号被检出,相同条件下,采用Ag-TiO₂时ESK信号明显增强,银用量为10%时比1%的更强。因此半导体TiO₂粒子表面进行银修饰后可显著提高光催化能力。     

Crystal growth,spectral properties and Judd–Ofelt analysis of Pr: CaF_2-YF_3

The 0.6 at.% Pr~(3+)-doped CaF_2-YF_3 crystal was successfully grown by the temperature gradient technique(TGT).X-ray diffraction analysis showed that the grown crystal still had cubic structure. The absorption spectrum, emission spectrum, Judd–Ofelt analysis and fluorescence decay curve at room temperature were discussed. The fluorescence lifetime of Pr: CaF_2-YF_3 crystal was 45.46 μs, and the σem ·τ of ~3P_0→~3H_6 and ~3P_0→~3F_2 transitions were calculated to be 80.92 × 10~(-20) cm~2·μs and 388.7 × 10~(-20) cm~2·μs, respectively. The FWHMs are 20.1 nm and 6.8 nm, which are higher than those of Pr: LiYF_4, Pr:LiLuF_4, Pr: LiGdF_4 and Pr: BaY_2F_8 crystals. The results show that the Pr: CaF_2-YF_3 crystal is expected to achieve 605 nm orange light and 642 nm red light laser operation.     

Investigation on the Cs 6S1/2 to 7D electric quadrupole transition via monochromatic two-photon process at 767 nm

We experimentally demonstrate the cesium electric quadrupole transition from the 6S_1/2 ground state to the 7D_3/2,5/2 excited state through a virtual level by using a single laser at 767 nm. The excited state energy level population is characterized by varying the laser power, the temperature of the vapor, and the polarization combinations of the laser beams. The optimized experimental parameters are obtained for a high resolution transition interval identification. The magnetic dipole coupling constant A and electric quadrupole coupling constant B for the 7D_3/2,5/2 states are precisely determined by using the hyperfine levels intervals. The results, A = 7.39 (0.06) MHz, B = −0.19 (0.18) MHz for the 7D_3/2 state, and A = −1.79 (0.05) MHz, B =1.05 (0.29) MHz for the 7D_5/2 state, are in good agreement with the previous reported results. This work is beneficial for the determination of atomic structure information and parity non-conservation, which paves the way for the field of precision measurements and atomic physics.