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1.
Atomic krypton was excited in presence of SF6 by an intense electron beam. The radiation emitted by the Kr2F1(2B2→ A1) transition was studied at 430 nm using time resolved spectroscopic techniques. The radiative lifetimes of Kr2F1 and of Kr12 were found to be 200 ns and 270 ns respectively. 相似文献
2.
Gas mixtures containing atomic krypton and carbon-tetrachloride were excited using intense electron beam pulses. The fluorescence produced by Kr2Cl1 was studied using time-resolved spectroscopic techniques. The lifetime (470 ns) and the quenching rate constants of Kr2Cl1 were deduced from the measurements. 相似文献
3.
Broad band emission of KrF1 centered at about 400 nm was observed in various mixtures containing Kr and fluorinated compounds. This emission was resolved against the more intense Kr2F1 broad band emission at the same wavelengths due to its temporal behaviour and its different pressure dependence. Its radiative lifetime is 16 ns and it is tentatively ascribed to the 3 2∑+ → 1 2Π transition. 相似文献
4.
5.
L. Museur A.V. Kanaev M.C. Castex L. Moussavizadeh R. von Pietrowski T. Möller 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1999,7(1):73-78
Charge-transfer reactions are observed in a photoluminescence study of NF3\rm NF_3-doped free krypton clusters. They show up in emissions from Kr+F-\rm Kr^{+}F^{-}free excimers ejected from the clusters, and from excited Kr2+F-\rm Kr_2^{+}F^{-}and Kr2+(NF3)m-{\rm Kr}_2^{+}({\rm NF}_3)_m^{-} (m 3(m\geq 1) solvated in the clusters. The results show that reaction dynamics in clusters differs considerably from that in the gas and solid phases. 相似文献
6.
A fast discharge KrF laser system (λ = 248.5 nm) has been operated at 25 mJ/pulse, 3.0 MW peak power in high pressure He: Kr: fluoride mixtures containing low concentrations of both krypton and the fluorine donors N2F4, NF3 and SF6. Lasing action is reported for the first time in N2F4 and SF6 with optimum energy output at 750 and 160 mJ/l respectively. 相似文献
7.
M. Sekita 《Journal of luminescence》1981,22(4):335-347
The emission and excitation spectra of the Bi2Ge3O9:Eu crystal are observed at 77 K and 297 K. The spectra contain groups of sharp lines which are attributed to the transitions within 4f6 (Eu3+) configuration. The numbers of Stark splitting of terminal levels of transitions from 5D0 and 7F0 multiplets indicate that Eu3+ substitutes for Bi3+ in Bi2Ge3O9. Tentative assignment of Stark levels of 7F0-4 multiplets is made to crystal quantum numbers of C3 symmetry which represents the site symmetry of Bi3+ in Bi2Ge3O9. The following set of values of crystal field parameters of the C3 point group is found to give the best overall agreement between the observed energy levels and the calculated levels: B20 = -533.84 cm-1, B40 = 1085.99 cm-1, Re(B43) = 327.57 cm-1, Im(B43) = 75.209 cm-1, B60 = 185.02 cm-1, Re(B63) = - 68.475 cm-1, Im(B63) = - 300.45 cm-1, Re(B66) = 137.24 cm-1 and Im(B66) = 882.29 cm-1. 相似文献
8.
Vibration-rotation spectra of the parallel ν5 band of hexafluorodisilane have been measured in a supersonic free jet with 0.001 cm−1 resolution. Three isotopic species, 28,28Si2F6, 28,29Si2F6, and 28,30Si2F6, have been studied. The effect of internal rotation is not observed, indicating that the splitting is smaller than our spectral resolution. A very weak parallel band observed with a slight red shift from the ν5 fundamental band has been assigned tentatively to the (ν4 + ν5)-ν4 hot band. 相似文献
9.
Keiichi Nagai Chikashi Yamada Yasuki Endo Eizi Hirota 《Journal of Molecular Spectroscopy》1981,90(1):249-272
The ν1 (CO stretching) and ν2 (CF stretching) bands of the FCO radical were observed with Doppler-limited resolution by an infrared diode laser spectrometer with Zeeman and source modulation. The FCO radical was generated by a 60-Hz discharge in one of the following three gas mixtures: O2 + C2F4, CO + SF6, and CO + C2F4, all diluted with He. The observed spectra were analyzed to determine the rotational constants, the centrifugal distortion constants, and the spin-rotation interaction constants. The band origins, 1861.6372(1) and 1026.1283(1) cm?1 [with standard errors in parentheses], which were obtained, were found to agree well with matrix data, 1857 and 1023 cm?1, respectively. The assignment of the observed spectra to the FCO radical was further supported by observing the ν1 band of F13CO, which was obtained from 13CO and SF6. The molecular structure and the force field of FCO are briefly discussed by using molecular constants obtained from the observed spectra. 相似文献
10.
S.V.J. Lakshman S. Buddhudu 《Journal of Quantitative Spectroscopy & Radiative Transfer》1980,24(3):251-257
The values of the Slater-Condon (F2, F4, F6), Racah (E1, E2, E3) and Lande ξ4f coefficients the nephelauxetic ratio (β), the bonding parameter (σ), and the Judd-Ofelt intensity (Tλ) parameters have been calculated from the reported absorption spectra of Pr3+, Nd3+, and Er3+ ions in an aprotic solvent SeOCl2 acidified with antimony pentachloride. The nature of the bonding is suggested to be covalent for praseodymium, neodymium and erbium ions in the laser liquid in view of the magnitude of the respective bonding parameters. 相似文献
11.
在室温下,测量了Er:Tm:NaY(WO4)2晶体的吸收光谱、激发光谱、发射光谱以及上转换发光,并运用J-O理论对测量的结果进行了计算,得出了Er:Tm:NaY(WO4)2晶体的强度参数.报道了Tm,Er离子间特殊的能量传递和相关上转换,解释了离子间的能级跃迁过程.同时,对于Er增强Tm离子近红外发光的特性也作了充分研究.
关键词:
4)2晶体')" href="#">Er:Tm:NaY(WO4)2晶体
吸收光谱
发射光谱
激发光谱
上转换 相似文献
12.
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800nm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Tm3+:NaY(WO4)2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.
关键词:
3+离子')" href="#">Tm3+离子
4)2晶体')" href="#">NaY(WO4)2晶体
上转换
浓度猝灭 相似文献
13.
The behavior of the desorbing F+ ion current from electron bombarded CCl2F2, C2H2F2 and C2F6 adsorbed on tungsten has been used to investigate the processes of adsorption and desorption of these gases. For tungsten near room temperature, measurements of the F+ ion current as a function of electron bombardment time indicated very similar or even identical F+-yielding adsorbed species resulting from adsorption of either CCl2F2 or C2H2F2 and widely different species from C2F6. Cl+ ions were also observed to desorb from CCl2F2 ad-layers. The behavior of the Cl+ ion current with time during electron bombardment indicated electronic conversion between adsorbed binding modes. Complementary investigations on the interaction of CCl2F2, C2H2F2 and C2F6 with tungsten were carried out by thermal desorption experiments in which the F+ ion signal was used to observe the coverage decrease of the F+-yielding species. The experiments were performed at tungsten temperatures in the 1200–1600 K range. It was concluded that the F+-yielding adsorbed species from CCl2F2 and C2H2F2 were strongly bound to the tungsten surface. The F+-yielding species from C2F6 were found to be weakly bound. From a comparison of the ESD and thermal desorption results, the possibility of dissociative adsorption as well as the nature of the adsorbed species is discussed. 相似文献
14.
Crystallographic, micro-D.T.A., dielectric and pyroelectric measurements have been performed for the Rb2KMO3F3, Cs2KMO3F3 and Cs2RbMO3F3 (M = Mo, W) compounds. Two types of transitions have been detected : the first one, for Rb2KMoO3F3 at low temperature, is due to the disappearance of the superstructure detected for Rb3MoO3F3α, the second one is of ferroelectric - paraelectric type (Rb2KMO3F3 and Cs2RbMO3F3 ; M = Mo, W). The transition temperatures have been compared vs the size of the alcaline ions and the nature of the M-O bonds. The increase of the transition temperatures from the A2A'MO3F3 to the A3MO3F3 compounds is likely due to the simultaneous presence of the A+ cations in the former ones in 6 and 12 coordination sites. 相似文献
15.
Seven absorption group-bands (1D2, 1G4, 3F2, 3F3, 3H4, 3H5, 3F4) of Tm3+ in YVO4 single crystals have been observed in the orientation absorption spectra recorded in the spectral range from 200 to 4000 nm at 300K. The integrated absorption cross section for each group-band was accurately evaluated. On the assumption that the anisotropy of this uni-axial crystal is small, the Judd-Ofelt theory was extended for the calculation of 4f-4f transition intensities of Tm3+ in YVO4. Two sets of phenomenological intensity parameters were derived from a least-squares-fit procedure. For c-axis cut sample we have Ω2=10.18 (10-20cm2), Ω4=1.96 (10-20cm2), Ω6=0.75 (10-20cm2).For a-axis cut sample we have Ω2=8.20 (10-20cm2), Ω4=2.47 (10-20cm2), Ω6=0.91 (10-20cm2). The anisotropy of the optical absorption intensities of Tm3+:YVO4 was theoretically analyzed in detail. 相似文献
16.
P. Haro-González L. L. Martín I. R. Martín M. Berkowski W. Ryba-Romanowski 《Applied physics. B, Lasers and optics》2011,103(3):597-602
Comparative investigation of the optical amplification properties of dysprosium doped Gd2SiO5, Lu2SiO5 and YAl3(BO3)4 single crystals was performed in a pump-and-probe experiment. High power laser pulses at 475 nm were used as the pump source
in order to strongly populate the 4F9/2 level of the Dy3+ ions due to ground state absorption. Low signal beam cw radiation at 574 nm was used as the probe beam to stimulate the emission
associated with the 4F9/2→6H13/2 electronic transition of the Dy3+ ions. The process was modelled as a three levels system, and their populations were analysed and simulated in order to study
the gain dynamics. Positive optical gain was observed and compared in these crystals. These results confirmed that among the
systems studied the Dy3+-doped YAl3(BO3)4 single crystal can be considered as a good candidate to develop an optical amplifier employing the 4F9/2→6H13/2 transition at around 574 nm which is the first step to consider as laser active media. 相似文献
17.
Takao Itoh 《Journal of Molecular Spectroscopy》2008,252(2):115-120
Fluorescence and excitation spectra of coronene vapor have been measured under different conditions. Weak emission which can be regarded as the fluorescence from the third excited singlet state, S3(1E1u), was observed in addition to the S1(1B2u) and S2(1B1u) fluorescence. The observed S2 and S3 fluorescence are substantially different from those reported previously for coronene vapor. Addition of oxygen resulted in significant decrease of the S1 fluorescence intensity, but did not affect the S2 fluorescence intensity, indicating the faster decay rate of the S2 state than that of S1. Excitation energy dependence of the S1, S2 and S3 fluorescence quantum yields (ΦF(S1), ΦF(S2) and ΦF(S3), respectively) revealed that ΦF(S1) decreases with increasing excitation energy, while ΦF(S2) and ΦF(S3) increase significantly. The quantum yield ratios, ΦF(S2)/ΦF(S1) and ΦF(S3)/ΦF(S2), obtained as a function of excitation energy are correlated with the ratios of the relative internal conversion rates. 相似文献
18.
Optical spectral studies of Pr3+ in PrCl3 complexes with MgCl2, CaCl2, CdCl2 and NH4Cl have been carried out, and the second derivative spectra of these five Pr3+ complexes are reported. From the observed features of the 3P2 and 1D2 bands, crystal field (A20, A40) parameters were evaluated assuming C3h symmetry for Pr3+ in these complexes. The Slater-Condon(F2, F4 and F6), configuration interaction (α, β) and spin-orbit (ξ4?), Racah (E1,E2 and E3), nephelauxetic (β), bonding (δ) and Judd-Ofelt (T2, T4 and T6) intensity parameters are evaluated. Theoretical estimates of spectral intensities calculated from Judd-Ofelt and electric (Sed)-magnetic (Smd) dipole linestrength methods are in good agreement with the observed values. The radiative lifetimes of elctronic excited states 3P1, 3P0, and 1D2 of Pr3+ in these five different hosts have been theoretically estimated. 相似文献
19.
S.A. Lourenço N.O. Dantas W.E.F. Ayta M.C. Filadelpho M.J.V. Bell 《Journal of luminescence》2011,131(5):850-126
In this work, Eu3+-doped lead borosilicate glasses (SiO2-B2O3-PbO2) synthesized by fusion method had their optical properties investigated as a function of temperature. Atomic Force Microscopy images obtained for a glass matrix annealed at 350 and 500 °C show a precipitated crystalline phase with sizes 11 and 21 nm, respectively. Besides, as the temperature increases from 350 to 300 K a strong Eu3+ photoluminescence (PL) enhancement takes place. This anomalous feature is attributed to the thermally activated carrier transfer process from nanocrystals and charged intrinsic defects states to Eu3+ energy levels. In addition, the PL peaks in this temperature range were assigned to the Eu3+ transitions 5D0→7F2, at 612 nm, 5D0→7F1, at 595 nm, and 5D0→7F0, at 585 nm. It was also observed that the 5D0→7F3 and 5D0→7F4 PL bands at 655 and 700 nm, respectively, show a continuous decrease in intensity as the temperature increases. 相似文献
20.
Structures and luminescence properties of Yb3+ in the double perovskites Ba2YB'O6 (B'=Ta5+, Nb5+) phosphors
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The Yb3+ doped Ba2YB'O6 (B'=Ta5+, Nb5+) were prepared by high temperature solid-state reaction method, their structures were determined by x-ray diffraction and refined by Rietveld method. The diffuse reflection absorption, excitation and emission spectra of Yb3+:Ba2YB'O6 (B'=,Ta5+, Nb5+) were measured at room temperature. Under the excitation of ultraviolet light, these phosphors exhibit broad charge transfer band emissions of TaO6 or NbO6 centre with large Stokes shift. The Yb3+ doped into these hosts are situated at Y3+ sites of cubic symmetry (Oh). The experimental energy levels of Yb3+ in Ba2YTaO6 and Ba2YNbO6 were determined by photoluminescence and diffuse reflection absorption spectra. Their wavefunctions and theoretical energy levels were obtained by diagonalising the Hamiltonian matrix. The experimental energy levels were fitted by Levenberg--Marquardt iteration algorithm to determine crystal field parameters. Then, the magnetic-pole transition line strengths of Yb3+:Ba2YB'O6(B'=Ta5+, Nb5+) from (2F5/2)Γ8- to the low-energy states were calculated. 相似文献