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951.
Li-jing Gong Ying-hui Wang Zhi-hui Kang Tian-hao Huang Ran Lu Han-zhuang Zhang 《化学物理学报(中文版)》2012,25(6):636-641
We investigate the fluorene-vinylene unit dependent photo-physical properties of multi-branched truxene based oligomers (Tr-OFVn, n=1-4) employing steady-state absorption and emission spectroscopy, transient absorption spectroscopy, two-photon fluorescence, and z-scan technique. The results show that the increasing of fluorene-vinylene unit leads to a red-shift in the spectra of absorption and fluorescence, and shortens the excited state lifetime. Meanwhile, two-photon fluorescence efficiency and two-photon absorption cross section of truxene based oligomers gradually enhance in company with the extension of π-conjugated length. In addition, the values of two-photon absorption cross section modeled on the sum-over-state approach agree well with the experimental ones. The results indicate multi-branched truxene based oligomers bearing oligo(fluorene-vinylene) arms are promisingorganic materials for two-photon applications. 相似文献
952.
褐钇铌矿族矿物的可见光光致发光谱和吸收谱研究 总被引:1,自引:0,他引:1
测定并讨论了白云鄂博变生态和退火晶态褐钇铌矿族矿物在 4 88 0和 51 4 5nm激光激发下的光致发光谱。分析表明 ,该族矿物的发光中心是Er3 和Eu3 ,其中褐钇铌矿的发光主要由Er3 产生 ,而Eu3 和Er3 的共同发光构成褐铈铌矿的发光谱。可见光吸收谱显示 ,Nd3 可能是该族矿物光致发光的重要敏化剂。 相似文献
953.
十六种活血化瘀中草药中微量元素的测定 总被引:10,自引:0,他引:10
用原子吸收光谱法对十六种活血化瘀中草药中十种微量元素进行了测定。方法的回收率为95.0% ̄105.0%,相对标准偏差小于0.03%,结果表明,该法具有操作简单,快速和准确度高等优点。 相似文献
954.
955.
Prof. Kevin D. Belfield Dr. Mykhailo V. Bondar Alma R. Morales Xiling Yue Dr. Gheorghe Luchita Dr. Olga V. Przhonska Dr. Olexy D. Kachkovsky 《Chemphyschem》2012,13(15):3481-3491
The synthesis, comprehensive linear photophysical characterization, two‐photon absorption (2PA), steady‐state and time‐resolved stimulated emission depletion properties of a new fluorene derivative, (E)‐1‐(2‐(di‐p‐tolylamino)‐9,9‐diethyl‐9H‐fluoren‐7‐yl)‐3‐(thiophen‐2‐yl)prop‐2‐en‐1‐one ( 1 ), are reported. The primary linear spectral properties, including excitation anisotropy, fluorescence lifetimes, and photostability, were investigated in a number of aprotic solvents at room temperature. The degenerate 2PA spectra of 1 were obtained with open‐aperture Z‐scan and two‐photon induced fluorescence methods, using a 1 kHz femtosecond laser system, and maximum 2PA cross‐sections of ~400–600 GM were obtained. The nature of the electronic absorption processes in 1 was investigated by DFT‐based quantum chemical methods implemented in the Gaussian 09 program. The one‐ and two‐photon stimulated emission spectra of 1 were measured over a broad spectral range using a femtosecond pump–probe‐based fluorescence quenching technique, while a new methodology for time‐resolved fluorescence emission spectroscopy is proposed. An effective application of 1 in fluorescence bioimaging was demonstrated by means of one‐ and two‐photon fluorescence microscopy images of HCT 116 cells containing dye encapsulated micelles. 相似文献
956.
Agnieszka Nowak‐Król Dr. Craig J. Wilson Dr. Mikhail Drobizhev Dmitry V. Kondratuk Prof. Aleksander Rebane Prof. Harry L. Anderson Prof. Daniel T. Gryko 《Chemphyschem》2012,13(17):3966-3972
We show that peripheral nitro groups enhance the maximum two‐photon absorption cross‐section of trans‐A2B2‐porphyrins bearing two phenylethynyl substituents by more than one order of magnitude. Maximum values as high as 1000 GM result from realization of suitable conditions for effective resonance enhancement along with a lowering of the energy and intensification of the two‐photon allowed transitions in the Soret region. 相似文献
957.
958.
《Journal of Coordination Chemistry》2012,65(20):3727-3740
In this article, the nonlinear optical characterizations and optical limiting properties of metal-free (2), zinc (3), and indium (4) tetra 4-(2-mercaptopyridine) phthalocyanines are discussed. Nonlinear optical properties of the samples were evaluated using Z-scan at 532 nm and 10 ns pulse in CHCl3, and doped on poly(bisphenol A carbonate) (PBC) thin films. Thin films for 2, 3, and 4 are represented as 2-PBC, 3-PBC, and 4-PBC, respectively. We observed two-photon absorption (2PA) and strong reverse saturable absorption as the dominant mechanisms at nanosecond laser excitation in solution and thin films. By virtue of the magnitude of absorption coefficients and other nonlinear optical parameters estimated in this work, sample 4 was found to exhibit strongest nonlinear optical properties followed by 3, while 2 is the weakest nonlinear absorber of the studied samples. Large third-order susceptibility (1.46 × 10?9 esu and 7.74 × 10?10 esu) and hyperpolarizability (2.13 × 10?28 and 8.37 × 10?29 esu) were estimated for 4-PBC and 3-PBC, respectively. Our studies show that these molecules are suitable candidates for practical passive optical limiters. 相似文献
959.
《Journal of Coordination Chemistry》2012,65(12):2075-2087
Nickel phthalocyanine (NiPc, 1) periphery has been decorated by alkyl chains of varying chain length via [1,3,4]-oxadiazole moiety (NiPcs 3a–3f). All the newly synthesized compounds NiPcs 3a–3d have been completely characterized by elemental analysis, FT-IR, solid-state UV-Vis, and solid-state 13C NMR spectroscopy, in addition to X-ray diffraction, scanning electron microscopy, and thermal analysis. The effect of chain length in the NiPc periphery on electronic absorption and DC electrical conductivity has been investigated. 相似文献
960.
含三螺吡喃单元大环分子的合成和酸致变色效应 总被引:1,自引:1,他引:1
合成了含有3个螺吡喃单元的大环分子,采用点击化学方法实现高效的闭环反应,大环分子产率为64%。 使用红外、核磁和质谱等方法检测和表征了反应中间产物和目标产物,质谱分析结果证实环化结构。 使用紫外-可见光谱仪观察到大环产物和线性螺吡喃前体分子在pH值接近4时的酸致变色效应。 与线性螺吡喃前体分子的最大紫外吸收峰位置(476 nm)相比,螺吡喃大环分子在最大紫外吸收峰位置(464 nm)发生蓝移。 螺吡喃大环分子比线性前体分子具有更大的摩尔消光系数,其pH响应性能更加优异。 相似文献