纳米相氟氧化物玻璃陶瓷Tm（0.35）Yb（5）∶FOV的上转换发光

研究了纳米相氟氧化物玻璃陶瓷Tm(0.35)Yb(5)∶FOV在975nm半导体激光激发下的上转换发光。发现了位于363.6,(462.6,477.0),648.7,(699.7,680.7)和(777.6,800.7nm)的几条上转换发光线,它们是Tm3 离子的1D2→3H6,1G4→3H6,1G4→3F4,3F3→3H6和3H4→3H6的荧光跃迁。为了确认它们的上转换机理,还测量了上转换发光强度F随975nm泵浦激光功率P改变的双对数曲线,结果证实了1D2能级的上转换发光部分是五光子上转换发光,而1G4能级和3H4能级的上转换发光则是三光子和双光子上转换发光。     

Tm(0.1)Yb(10.9)氟氧化物玻璃的直接上转换敏化发光

本文首次研究了Tm(0.1)Yb(10.9)氟氧化物玻璃在966nm半导体激光激发下的直接上转换敏化发光现象。测量发现存在很强的^1G4→^3H6的474nm三光子和较弱的^1D2→^3H6的362nm,^1D2→^3F4的452nm,^1G4→^3F4的650nm三光子以及^3F3→^3H6的681nm二光子上转换发光。并对他们的上转换机理做了简要的讨论分析。     

Tm：YVO4晶体中Tm^3＋的发光研究

测量了Tm:YVO4晶体的吸收光谱,以346nm,363nm(^1D2),475nm(^1G4),698nm(^3F2,^3F3)和801nm(^3H4)光激发时的发射光谱,以及位于454nm(^1D2→^3F4),475nm(^1G4→^3H6),646nm(^1G4→^3F4),806nm(^3H4→^3H6)的荧光谱线的激发光谱,对测量的结果进行了详细分析,解释了离子能级间的跃迁过程,提出了Tm:YVO4晶体基质与Tm^3 之间的能量交换的概念和新的跃迁通道,证实了存在^1D2 ^3H6→^1G4 ^3F4以及^1G4 ^3H6→^3H4 ^3H5的能量传递过程,还可能存在交叉弛豫过程^1G4 ^H6→^3F2 ^3F4. 这些过程使得Tm:YVO4晶体难以实现^1D2能级上转换发光（454nm左右）,但475nm的上转换发光（^1G4→^3H6)较强,^3F4能级是潜在红外激光发射能级。     

Tm∶YVO4晶体中Tm3+的发光研究

测量了Tm∶YVO4 晶体的吸收光谱 ,以 34 6nm、36 3nm(1D2 )、475nm(1G4 )、6 98nm (3 F2 ,3 F3 )和 80 1nm(3 H4 )光激发时的发射光谱 ,以及位于 45 4nm (1D2 → 3 F4 )、475nm (1G4 → 3 H6)、6 46nm (1G4 → 3 F4 )、80 6nm(3 H4 →3 H6)的荧光谱线的激发光谱 ,对测量的结果进行了详细分析 ,解释了离子能级间的跃迁过程。提出了Tm∶YVO4 晶体基质与Tm3 + 之间的能量交换的概念和新的跃迁通道 ,证实了存在1D2 +3 H6→1G4 +3 F4 以及1G4 +3 H6→3 H4 +3 H5的能量传递过程 ,还可能存在交叉弛豫过程 1G4 +3 H6→3 F2 +3 F4 。这些过程使得Tm∶YVO4 晶体难以实现1D2 能级上转换发光 (4 5 4nm左右 ) ,但 475nm的上转换发光 (1G4 →3 H6)较强 ,3 F4 能级是潜在红外激光发射能级。     

Tm3+/Yb3+共掺杂ZBLAN玻璃的多光子紫外上转换发光

利用光谱分析手段研究了熔融淬火法制备的Tm和Yb共掺杂的重金属氟化物玻璃ZrF4-BaF2-LaF3-AlF3-NaF的上转换发光性质.在980 nm连续激光的激发下,观察到了较强的363 nm(1D2→3H6),347nm(1I6→3F4)和291 nm(1I6→3H6)的紫外上转换发光,以及中心位于454 nm,4...     

Tm3+离子掺杂的钨酸钇钠晶体中浓度猝灭效应的研究

测量了Tm3+离子不同浓度(0.5at.%,3 at.%,5 at.%)掺杂的NaY(WO4)2晶体在800 nm激光二极管激发下的上转换发射光谱.结合吸收谱、荧光谱和由Judd-Ofelt理论计算的光谱参数,详细分析了Tm36:NaY(WO4),晶体中上转换能量传递机理和离子浓度对上转换发射的影响.讨论了四种影响上转换发光效率的离子间相互作用机理:3H5+1G4→3H6+1D2,3H5+3H5→3H6+3F3,1G4+3H6→3F4+3F3,1G4+3H6→3F3+3F4,并根据Miyakawa-Dexter理论定量计算了各过程的发生概率.论证了交叉弛豫和共协上转换等浓度猝灭效应是影响Tm3+离子蓝色上转换荧光发射效率的主要因素.     

不同波长激发下YLiF_4∶Er~(3+),Tm~(3+),Yb~(3+)的发光

水热法合成了YL iF4∶Er3 ,Tm3 ,Yb3 ,其中Er3 、Yb3 和Tm3 的摩尔分数分别为1%、1.5%和2%。当用355 nm光激发时,其发光为蓝色,峰值位于450 nm,对应于Tm3 的1D2→3F4跃迁。用378 nm激发时,发光为绿色,主要发光峰位于552 nm。980 nm光激发时,发光为白色,发光峰分别位于665(651),552(543),484,450 nm处,并在648 nm处还观察到了一个发光峰,其中最强的发射为红光。YL iF4∶Er3 ,Tm3 ,Yb3 的蓝光来源于Tm3 的激发态1G4到基态3H6的跃迁,绿光来源于Er3 的4S3/2和2H11/2到基态4I15/2的跃迁,红光既来源于Tm3 的1G4→3F4的跃迁,也来源于Er3 的4F9/2→4I15/2的跃迁。在上转换发光中,还探测到了紫外光359 nm的发射。监测665 nm得到的激发光谱不同于监测552 nm的激发光谱,在665 nm的激发光谱中出现了对应Tm3 的1G4能级的峰。在双对数曲线中,蓝光484 nm、绿光552 nm和红光665 nm的斜率分别为2.25、2.28和2.21,紫外光359 nm的斜率为2.85。因此在980 nm激发下,蓝光484 nm、绿光552 nm和红光665 nm都是双光子过程,紫外光359 nm的发射是三光子过程。     

掺铥钨酸盐晶体的光谱研究

采用丘克拉斯基法生长出Tm3+:BaWO4单晶,并在室温下测量了掺铥钨酸钡晶体的吸收光谱。Tm3+:BaWO4晶体在268nm和362nm光源激发下,可以分别观测到位于477.2 nm(1G4→3H6)和455.5nm(1D2→3F4)的可见荧光。本文还报道了在Nd:YAG激光器产生波长1.06μm强脉冲激光激发ZnWO4:Tm3+单晶时,测得Tm3+离子1G4至3H6跃迁的波长在484 nm范围的蓝色上转换荧光光谱。     

Ca3Y2Si3O12∶Tm3+,Yb3+上转换发光粉的制备与发光性能研究

采用高温固相法成功制备了Ca3Y2Si3O12∶Tm3+,Yb3+上转换蓝色发光材料.在980 nm红外激光器激发下,发光粉呈现强烈的蓝光(475 nm)和近红外光(810 nm)以及较弱的红光(650 nm)发射,分别归因于Tm3+离子的1G4 →3H6、3H4→3H6和1 G4→3 F4能级跃迁.随着Yb3+离子浓度的增加,发光粉上转换发射强度和发光亮度均呈现先增强后减弱的变化趋势.在最佳掺杂浓度下(Yb3+摩尔分数为15％),蓝、红光强度分支比为12∶1,色坐标为(0.129 2,0.152 3).在3.9 W/cm2激发功率密度下,发光亮度可达6.8 cd/m2.上述结果证实,所制备发光粉呈现优异的蓝光上转换发射特性并具有潜在的应用价值.发光强度和激发光功率关系表明,所得上转换发射为三光子和双光子吸收过程.借助Tm-Yb体系能级结构详细讨论了上转换发射的跃迁机制.     

Pr(0.5):ZBLAN的双频激发上转换发光的研究

报道了Pr(0.5):ZBLAN玻璃在双频双光束光源激发下的激发态上转换现象.发现上转换发射谱的荧光与常规荧光发射谱的荧光一致，还发现双频激发下的上转换激发谱有3个明显的谱峰，它们依此对应于788.5nm 1G4→3P2,850.5nm 1G4→1I6和805.0nm 3H6→1D2的激发态吸收跃迁，而大的850.5nm上转换激发谱峰是由大的1G4(Pr3+ )→1I6(Pr3+)跃迁的振子强度f=23.04×10-6所致.这说明起源于1G4能级的激发态吸收上转换尤其1G4(Pr3+)→1I6(Pr3+)     

Theoretical Study of the Collision-Induced Double Transition CO(2) (nu(3) = 1) + N(2) (nu(1) = 1) <-- CO(2) (nu(3) = 0) + N(2) (nu(1) = 0) at 296 K

A procedure is presented for the calculation of the double vibrational collision-induced absorption CO(2) (nu(3) = 1) + N(2) (nu(1) = 1) <-- CO(2) (nu(3) = 0) + N(2) (nu(1) = 0) on the basis of quantum lineshapes computed using an isotropic potential and dipole-induced dipole functions. The linestrengths and energies of the vibration-rotation transitions are treated explicitly for N(2), utilizing the HITRAN database for CO(2). The theoretical absorption profile is compared to recent experimental results. By narrowing the width of the individual lines contributing to the overall absorption profile relative to their values determined for N(2)-N(2) collision-induced absorption, excellent agreement between theory and experiment is obtained. Copyright 2000 Academic Press.     

First Observation of the nu(17)-nu(4) Difference Bands of Diborane (10)B(2)H(6) and (11)B(2)H(6)

An analysis of the nu(17)-nu(4) difference bands near 800 cm(-1) of two isotopic species, (10)B(2)H(6) and (11)B(2)H(6), of diborane has been carried out using infrared spectra recorded with a resolution of ca. 0.003 cm(-1). In addition, the nu(17) band of (10)B(2)H(6) has been recorded and assigned. Since this band in (11)B(2)H(6) had already been studied (R. L. Sams, T. A. Blake, S. W. Sharpe, J.-M. Flaud, and W. J. Lafferty, J. Mol. Spectrosc. 191, 331-342 (1998)), it was possible to derive precise energy levels and Hamiltonian constants for the 4(1) vibrational states of both isotopic species. Copyright 2000 Academic Press.     

The 2(3)Delta(g) State of (7)Li(2)

Using pulsed perturbation-facilitated optical-optical double resonance (PFOODR) spectroscopy, the 2(3)Delta(g) state of (7)Li(2) (electronic configuration (varsigma(g)2s) (4ddelta(g)), effective principal quantum number n* = 4.101) has been observed and assigned. Molecular constants and a RKR potential energy curve were obtained. The major molecular constants are Copyright 2000 Academic Press.     

The Perturbation between the G(1)Pi(g) and 2(1)Delta(g) States of (7)Li(2)

We have observed the rotational levels in the v = 2, 3, 5, 6, 7, and 8 vibrational manifolds of the 2(1)Delta(g) state of (7)Li(2) via the A(1)Sigma(+)(u) intermediate levels by DeltaLambda = 2 transitions. This violation of the DeltaLambda = 0, +/-1 selection rule is due to the interaction with the G(1)Pi(g) state. Band-by-band deperturbations of the G(1)Pi(g) approximately 2(1)Delta(g) (v(Pi), v(Delta)) = (11, 2), (12, 3), (15, 5), (16, 6), (18, 7), and (19, 8) bands have been performed. Deperturbed molecular constants and rotational-electronic interaction parameters are reported here. Copyright 2000 Academic Press.     

Rovibrational Intensities of the (00(0)3) <-- (10(0)0) Dyad Absorption Bands of (12)C(16)O(2)

Absolute line intensities of (12)C(16)O(2) are experimentally measured for the first time for the (00(0)3)(I) <-- (10(0)0)(II) band at 5687.17 cm(-1) and the (00(0)3)(I) <-- (10(0)0)(I) band at 5584.39 cm(-1). The spectra were obtained using a Bomem DA8 Fourier transform spectrometer and a 25-m base-path White cell at NASA-Ames Research Center. The rotationless bandstrengths at a temperature of 296 K and the Herman-Wallis parameters are S(0)(vib) = 6.68(30) x 10(-25) cm(-1)/(molecule/cm(2)); A(1) = 1.4(9) x 10(-4), and A(2) = -1.1(5) x 10(-5) for the (00(0)3)(I) <-- (10(0)0)(II) band and S(0)(vib) = 6.07(22) x 10(-25) cm(-1)/(molecule/cm(2)); A(1) = 5.2(1.5) x 10(-4) and A(2) = -4.0(7) x 10(-5) for the (00(0)3)(I) <-- (10(0)0)(I) band.     

CO2同位素分子16O12C16O, 16O12C17O, 16O13C17O配分函数研究

本文主要研究了CO2的三种同位素分子16O12C16O , 16O12C17O ,16O13C17O 70 K~6000 K的总内配分函数 (TIPS)。在总内配分函数的计算中, 转动配分函数的计算采用了McDowell的解析式法, 振动配分函数则采用了简谐振动近似(HOA)获得。最后通过将两配分函数乘积近似计算得出TIPS, 并将其70~3000 K的数据和HITRAN04数据进行了比较, 发现所得结果和数据库符合的较好, 且其误差可以近似看成一条直线。并通过对误差的拟合修订了高温区(3000~6000 K)的计算数据, 给出了在高温下的较为准确的TIPS值。     

Torsional Splitting in the nu(5) Fundamental Infrared Band of CH(3)CD(3) and (13)CH(3)CD(3)

The nu(5) fundamental (C-C stretching) of CH(3)CD(3) shows a resolved torsional structure, caused by perturbations due mainly to the linear dependence of the torsional potential barrier on the normal coordinate Q(5). We were able to analyze this structure and to assign vibration-rotation transition wavenumbers for all five torsional components, classified according to the symmetry species of the G(18)((3)) extended molecular group. The torsional splitting pattern is qualitatively similar to that of a nondegenerate vibrational state with an even number of excited torsional quanta v(6). Explorative calculations show that the main perturber system should consist of the torsional components of the vibrational ground state correlating with v(6)=4 in the high barrier limit. The strength of the perturbation on the E(r0) torsional components of nu(5) increases rapidly with r, the E(40) component being the most affected. The observed transition wavenumbers can be reasonably fitted by a simplified model containing independent effective vibration-rotation parameters for the five different torsional components of nu(5), for both CH(3)CD(3) and (13)CH(3)CD(3). The trend of the determined values of the effective vibrational wavenumbers and rotational parameters over the torsional components supports the proposed vibration-torsion interaction mechanism, responsible for the observed torsional splittings. A strong anomaly observed in the rotational intensity distribution of nu(5) is discussed. Copyright 2001 Academic Press.     

The v(1)+v(3) Bands of the (16)O(17)O(16)O and (16)O(16)O(17)O Isotopomers of Ozone

Using 0.002 cm(-1) resolution Fourier transform absorption spectra of an (17)O enriched ozone sample, an extensive analysis of the v(1)+v(3) bands of the (16)O(17)O(16)O and (16)O(16)O(17)O isotopomers of ozone has been performed for the first time. The experimental rotational levels of the (101) vibrational states were satisfactorily reproduced using a Hamiltonian matrix that takes into account the observed rovibrational resonances. More precisely, for (16)O(17)O(16)O, as for the other C(2v)-type ozone isotopomers, it was necessary to account for the Coriolis type resonances linking the (101) rotational levels with the levels of the (200) and (002) vibrational states and the Darling-Dennison interaction coupling the levels of (200) with those of (002). For the C(s)-type isotopomer, namely (16)O(16)O(17)O, as for (16)O(16)O(18)O and (16)O(18)O(18)O, it proved necessary to also account for an additional DeltaK(a)&equals+/-2 resonance involving the rotational levels from (101) and (002) (J.-M. Flaud and R. Bacis, Spectrochimica Acta Part A 54, 3-16 (1998)). Using a Hamiltonian matrix which takes these resonances explicitly into account, precise vibrational energies and rotational and coupling constants were deduced, leading to the following band centers: v(0)(v(1)+v(3))=2078.3496 cm(-1) for (16)O(17)O(16)O and v(0)(v(1)+v(3))=2098.8631 cm(-1) for (16)O(16)O(17)O. Copyright 2001 Academic Press.