Excitation of Doubly‐Charged Ion Emission Lines from a Grimm‐Style Glow Discharge Plasma—Comparison Between Yttrium and Zirconium

Spectra of yttrium and zirconium emitted from a Grimm‐style glow discharge plasma were investigated to elucidate the excitation mechanism of doubly‐charged ionic lines when using argon–helium mixed gas as well as argon gas alone. The energy sum for exciting doubly‐charged ion species of yttrium is slightly smaller compared to the case of zirconium, which yields an interesting correlation in the excitation energy between their ionic species and excited species of helium or argon. The Y III emission lines which were assigned to the 4p⁶5p–4p⁶5s(4p⁶4d) transitions could be observed in the argon–helium mixed gas plasma, but those were hardly excited with argon gas only. The Zr III emission lines did not appear in the spectra emitted by the argon gas plasma nor by the mixed gas plasma. A possible explanation for these phenomena is that the excitation of these ionic species is caused principally by collisional energy transfer from helium species to the analyte atoms.     

Photoinduced Charge Transfer Processes of Zinc Porphyrin Derivatives for Dye-sensitized Solar Cells

We studied the excitation energies of zinc porphyrin(ZnP) and zinc porphyrin analogues(ZnP-R) with long-range corrected(LC) density functional theory. We compared three recent LC functionals, wB97XD, CAM-B3LYP, LC-wPBE and functionals B3LYP with the experiments. It was found that the low energy excitation is well predicted for ZnP with the LC-wPBE functional based on 6-31G(d) basis set. Excited-state geometry optimizations for all the compounds were carried out. It was shown that upon the photo-excitation nearly 1 e transferred to the acceptor unit[dodecafluorosubphthalocyanine, SubPc(F)₁₂] and a highly polarized state formed in compound 5. But after the relaxation of the first excited state, the electron on the acceptor went back to the ZnP a little and then shifted from ZnP to the donor segment[bis(4-hexylphenyl)amino] partially. The computed excited-state radiative lifetime(τ) for compound 5 is 943 μs, which shows a reasonable agreement with the experimental observation. According to the long-lived exciton in strong push-pull compound 5, we proposed that electron injection to semiconductor might occur after vibrational relaxation of excited state.     

β-环糊精诱导SDBS激发光谱法定量及机理研究

采用β-环糊精诱导SDBS产生显著增强的激发光谱信号,通过激发的光谱信号与SDBS含量的对应关系定量存在较强干扰作用时的SDBS水溶液。研究结果表明,β-环糊精具有显著提高SDBS的检测范围和检测精度的作用,同时具有显著降低三采复配驱油剂中SDS、OP-10及HPAM等常用组分对SDBS定量产生的干扰影响。该方法的定量误差在2.0%以下,检测精度可达10-2～10-3 mg·L-1。在水溶液体系中,β-环糊精可自发与SDBS形成摩尔比为1：1型包结物,该包结物的吉布斯函变Δ_γGmΘ(298 K)为-11.064 kJ·mol-1,稳定常数K_a为87。结合FTIR分析推测出SDBS分子中苯环基团进入β-环糊精空腔内部形成稳定的包结物,是其产生激发光谱的根本原因。     

Excitation and emission processes of Tb in porous anodic alumina

The strong photoluminescence (PL) of porous anodic alumina (PAA) with terbium deposition is reported. PAA, which has a regular pore morphology, is considered an effective template for fabricating luminescent composites. Tb was deposited onto PAA films by immersion in alcoholic solution with terbium chloride followed by heat treatment. The PL spectra demonstrate typical bands of Tb³⁺ corresponding to ⁵D₄ → ⁷F_j (j = 3, 4, 5, 6,) electron transition, with the maximum at 18,360 cm⁻¹ (⁵D₄ → ⁷F₅). The PL mechanism of Tb³⁺ was systematically studied with annealing temperature. The non-radiative relaxation channel is provided by OH hydroxyls at the surface of porous anodic alumina and, after annealing at 900 °C, the PL yield is highly improved. The PL intensity of Tb³⁺ increases with laser power and a saturation phenomenon, associated with the ratio of Tb³⁺ to Tb⁴⁺ ions, is observed at approximately 90 W/cm². Based on a theoretical model, the optical cross-section σ of terbium in PAA is estimated, with a value close to that of other porous materials doped with the rare-earth elements.     

M3La(BO3)3(M=Ca,Sr,Ba)基质中Eu3+的光致发光

研究了M3La(BO3)3(M=Ca,Sr,Ba)基质中Eu3+的激发光谱和发射光谱.结果表明,最强激发峰均为394nm,并均有λ<300nm的较强电荷迁移带;按Ca-Sr-Ba的顺序,各发射峰峰值逐渐红移;Eu3+的最佳发射浓度分别为xEu3+=0.10、0.09、0.20;Eu3+的5D0→7F2跃迁发射的浓度猝灭机理分别为电偶极-四极、电偶极-偶极和电偶极-偶极相互作用.     

Structure and Excitation Dynamics of β-Carotene Aggregates in Cetyltrimethylammonium Bromide Micelle

The β-carotene(β-Car) aggregate was prepared by self-assembly in cetyltrimethylammonium bromide (CTAB) micelle. The ground state absorption measurement showed that the aggregate has J-type characteristics and resonance Raman spectra gave the intrinsic explanation of molecular interaction in aggregate. Upon excitation at the optical allowed S₂ state of aggregate, direct generation of triplet state via singlet fission(SF) mechanism was observed. Excitation dynamics was elucidated by fs-transient absorption spectroscopy and ns-flash photolysis, respectively. The triplet state life time of aggregate was found to be independent of the ambient oxygen molecules.     

Photoluminescence and Photoacoustic Spectroscopies of Fe3+ in the LiGa5O8–LiGaSiO4–Li5GaSi2O8 System

This report is devoted to the study of the low and room temperature photoluminescence and photoacoustic spectroscopy of the Fe³⁺ impurity ion in the LiGa₅O₈–LiGaSiO₄–Li₅GaSi₂O₈ system. The sample was obtained by solid-state reaction between β-Ga₂O₃, Li₂CO₃, SiO₂ and appropriated quantities of Fe₂O₃. It was investigated by X-ray diffraction to determine the formed phases and through photoluminescence, excitation and photoacoustic spectroscopy measurements. The broad absorption and emission bands in the visible and near-infrared spectral regions presented by that system constitute the motivation for this study. More specifically, the luminescence occurs over a large interval of wavelengths, between 400 nm and 800 nm.     

光动力学疗法新型光敏剂的光谱特性研究

实验研究了用于光动力学诊断和治疗的新型光敏剂二磺基二邻苯二甲酰亚胺甲基酞菁锌（ZnPcS2P)癌光啉（PsD-007)、血啉甲醚（HMME）以及早期应用于临床的血卟啉衍生物（HpD)分别在生理盐水和含10％人血清生理盐水中的光谱特性。结果表明：除ZnPcS2P2的最大吸收峰位于670nm之外，其余三种光敏剂在人血清环境中的最大吸收峰都位于405nm处，但与生理盐水环境相比索瑞（Soret)峰发生了12nm的红移。在波长为413和514.5nm光源激发下，HMME，HpD和PsD-007在人血清环境中的荧光发射峰都分别位于625和690nm，但413nm光源的激发效率比514.5nm光源高出3倍左右，而且HEEM的荧光激发效率最高，HpD次之，PsD-007最低。     

In vivo fluorescence imaging using two excitation and/or emission wavelengths for image contrast enhancement

Steady-state fluorescence imaging can be used in conjunction with selective exogenous or endogenous fluorescent compounds for the diagnosis of skin lesions, for example cancer. Depending on the excitation and emission properties of the fluorescent compound used, various excitation and/or emission wavelengths can be chosen in order to allow fluorescence imaging. Unwanted background signals such as autofluorescence and scattering can decrease the image quality and, hence, the diagnosis potential of this imaging method. We have used an inexpensive dual excitation and/or emission wavelength approach in order to suppress the unwanted background signal and allow contrast enhanced fluorescence imaging. One excitation and/or emission wavelength is at the corresponding maximum of the fluorescent compound, while the second is at a nearby excitation/emission minimum. The first image contains the emission from the fluorescent compound used combined with the signal from the unwanted background. The second image provides an image of just the unwanted background signal. The difference of both images taken, thus gives a contrast enhanced image of the skin lesion. The method relies on the assumption that the background signal does not change significantly due to the small changes in wavelength for excitation or emission. Image ratio methods have already been applied towards diagnosis of basal cell carcinomas after administration of aminolevulinic acid-induced protoporphyin IX. In this study, we describe in vivo measurements in mice where the second image, usually the background signal only, contains new unwanted image data. This simple method can successfully resolve the desired image, thus demonstrating the versatility of the image processing procedure.