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1.
For CH2+ molecular ions at 5 K we simulate the infrared absorption spectrum, and tabulate all strong absorption lines from 0 to 16 000 cm−1. We use ab initio potential energy, dipole moment, and transition moment surfaces in conjunction with our program system RENNER, which allows for the Renner-Teller effect and spin-orbit coupling in a full-dimensions calculation. This is done for the purpose of guiding our search for the matrix isolation spectrum; our attempts at finding this spectrum are also described.  相似文献   

2.
More than 250 rotationally resolved vibrational bands of the A2B2-X2A1 electronic transition of 15NO2 have been observed in the 14 300-18 000 cm−1 range. The bands have been recorded in a recently constructed setup designed for high resolution spectroscopy of jet cooled molecules by combining time gated fluorescence spectroscopy and molecular beam techniques. The majority of the observed bands has been rotationally assigned and can be identified as transitions starting from the vibrational ground state or from vibrationally excited (hot band) states. An exceptionally strong band is located at 14 851 cm−1 and studied in more detail as a typical benchmark transition to monitor 15NO2 in atmospheric remote sensing experiments. Standard rotational fit routines provide band origins, rotational and spin rotation constants. A subset of 177 vibronic levels of 2B2 vibronic symmetry has been analyzed in the energy range between 14 300 and 17 250 cm−1, in terms of integrated density and using Next Neighbor Distribution. It is found that the overall statistical properties and polyad structure of 15NO2 are comparable to those of 14NO2 but that the internal structures of the polyads are completely different. This is a direct consequence of the X2A1-A2B2 vibronic mixing.  相似文献   

3.
In this work, a full ligand-field energy matrix (10×10) diagonalization treatment for 3d1 ions in tetragonal symmetry is developed on the basis of the two-s.o.-coupling-parameter model. Spin Hamiltonian parameters (g factors g, g and hyperfine structure constants A, A) of the tetragonal V4+ center in Zn(antipyrine)2(NO3)2 are calculated from the complete energy matrix diagonalization method and the perturbation theory method. The calculated results from both methods are not only close to each other but also in good agreement with the experimental values. Furthermore, the compressed defect structure of V4+ center is discussed.  相似文献   

4.
A high-resolution Fourier transform spectrum of the D2MSe species (M = 82, 80, 78, 77, and 76) in the region 2300-2500 cm−1 was recorded for the first time and assigned. On the basis of these experimental data, rotation-vibration energies of the (1 1 0) and (0 1 1) vibrational states were fitted, and band centers, and rotational, centrifugal distortion, and resonance interaction parameters were determined for the main D280Se species. The obtained set of 32 fitted parameters reproduces the 647 rotation-vibration energies with a rms deviation of 0.00024 cm−1. The ν1 + ν2 and ν2 + ν3 bands of the other four isotopic species are analyzed as well.  相似文献   

5.
The reduction process of Bi3+, HTeO2+ and their mixtures on Au electrode surface was studied by cyclic voltammetry, linear sweep voltammetry, electrochemical impedance spectroscopy and chronoamperometry. XRD and EDS methods were also used to measure the reductive products prepared under different potentials and provide the evidences of the reactions. The results indicate that the reduction of HTeO2+ occurs at more positive potential than that of Bi3+, but its reduction rate is slower and adsorption phenomenon exists during its reduction process. Bi2Te3 compound can be obtained potentiostatically at a proper potential in all the mixed solutions with concentration ratio CHTe+O2/CBi3+ in our research range (0.1-10). But pure Bi2Te3 compound can only be obtained at 42 mV in the solution with concentration ratio CHTe+O2/CBi3+ equaling to 1. And the formation of Bi2Te3 compound is an inductive co-depositing process: (1) HTeO2+ + 4e + 3H+ → Te0 + 2H2O, (2) 3Te0 + 2Bi3+ + 6e → Bi2Te3.  相似文献   

6.
Modulated gain spectroscopy is a sensitive, widely applicable, rovibronically state selective, sub-Doppler, triple resonance method for examining excited vibronic levels which are Franck—Condon inaccessible from thermally populated levels of the electronic ground state. A cw optically pumped molecular laser (OPL) prepares a steady-state population in a selected, vibrationally highly excited, rotation-vibration level of the electronic ground state (the lower level of the OPL transition). An intensity-modulated, single frequency dye laser excites part of this intracavity OPL-prepared population to the level of interest, thereby causing an increase in the OPL population inversion density, and, in turn, its output power. As the frequency of the dye laser is scanned, resonances are selectively detected by the appearance of modulation on the OPL output power; discrimination against dye laser excitations out of levels unconnected with the OPL is nearly perfect. Sub-Doppler (≈300 MHz FWHM) transitions are observed, thereby extending knowledge of the Na2A1Σ+u state from v=44 to 62.  相似文献   

7.
Jidi Liu  Xue Yu  Jie Li 《Journal of luminescence》2010,130(11):2171-2174
A series of green phosphors Zn1.92−2xYxLixSiO4:0.08Mn2+ (0≤x≤0.03) were prepared by solid-state synthesis method. Phase and lattice parameters of the synthesized phosphors were characterized by powder X-ray diffractometer (XRD) and the co-doped effects of Y3+/Li+ upon emission intensity and decay time were investigated under 147 nm excitation. The results indicate that the co-doping of Y3+/Li+ has favorable influence on the photoluminescence properties of Zn2SiO4:Mn2+, and the optimal photoluminescence intensity of Zn1.90Y0.01Li0.01SiO4:0.08Mn2+ is 103% of that of commercial phosphor when the doping concentration of Y3+/Li+ is 0.01 mol. Additionally, the decay time of phosphor is much shortened and the decay time of Zn1.90Y0.01Li0.01SiO4:0.08Mn2+ is 3.39 ms, shorter by 1.83 ms than that of commercial product after Y3+/Li+ co-doping.  相似文献   

8.
Kinetics and mechanisms for reactions of OH with methanol and ethanol have been investigated at the CCSD(T)/6-311 + G(3df2p)//MP2/6-311 + G(3df2p) level of theory. The total and individual rate constants, and product branching ratios for the reactions have been computed in the temperature range 200-3000 K with variational transition state theory by including the effects of multiple reflections above the wells of their pre-reaction complexes, quantum-mechanical tunneling and hindered internal rotations. The predicted results can be represented by the expressions k1 = 4.65 × 10−20 × T2.68 exp(414/T) and k2 = 9.11 × 10−20 × T2.58 exp(748/T) cm3 molecule−1 s−1 for the CH3OH and C2H5OH reactions, respectively. These results are in reasonable agreements with available experimental data except that of OH + C2H5OH in the high temperature range. The former reaction produces 96-89% of the H2O + CH2OH products, whereas the latter process produces 98-70% of H2O + CH3CHOH and 2-21% of the H2O + CH2CH2OH products in the temperature range computed (200-3000 K).  相似文献   

9.
Thirty-four rovibronic spectral lines of the Ω=1/2 component of the (4, 8) band in the A-X system of 35Cl2+ were observed in the range of 16,940-17,010 cm−1, employing optical heterodyne-enhanced velocity modulation spectroscopy. Nonlinear least-squares fitting the effective Hamiltonians results in precise band origin and other molecular constants of the levels involved.  相似文献   

10.
王杰敏  张蕾  施德恒  朱遵略  孙金锋 《物理学报》2012,61(15):153105-153105
采用包含Davidson修正多参考组态相互作用(MRCI)方法结合价态范围内的最大相关一致基As/aug-cc-pV5Z和O/aug-cc-pV6Z, 计算了AsO+ (X2+)和AsO+(A2∏)的势能曲线. 利用AsO+离子的势能曲线在同位素质量修正的基础上, 拟合出了同位素离子75As16O+75As18O+的两个电子态光谱常数. 对于X2+态的主要同位素离子75As16O+, 其光谱常数Re, ωe, ωexe, Be和αe分别为 0.15770 nm, 1091.07 cm-1, 5.02017 cm-1, 0.514826 cm-1和0.003123 cm-1; 对于A2∏态的主要同位素离子75As16O+, 其Te, Re, ωe, ωexe, Be和αe分别为5.248 eV, 0.16982 nm, 776.848 cm-1, 6.71941 cm-1, 0.443385 cm-1和0.003948 cm-1. 这些数据与已有的实验结果均符合很好. 通过求解核运动的径向薛定谔方程, 找到了J=0时AsO+(X2+)和AsO+(A2∏)的前20个振动态. 对于每一振动态, 还分别计算了它的振动能级、转动惯量及离心畸变常数, 并进行了同位素质量修正, 得到各同位素离子的分子常数. 这些结果与已有的实验值非常一致. 本文对于同位素离子75As16O+(X1+), 75As18O+(X1+), 75As16O+(A1∏)和75As16O+(A1∏)的光谱常数和分子常数属首次报导.  相似文献   

11.
Li2O-ZrO2-SiO2: Ho3+ glasses mixed with three interesting d-block elemental oxides, viz., Nb2O5, Ta2O5 and La2O3, were prepared. Optical absorption and photoluminescence spectra of these glasses have been recorded at room temperature. The luminescence spectra of Nb2O5 and Ta2O5 mixed Li2O-ZrO2-SiO2 glasses (free of Ho3+ ions) have also exhibited broad emission band in the blue region. This band is attributed to radiative recombination of self-trapped excitons (STEs) localized on substitutionally positioned octahedral Ta5+ and Nb5+ ions in the glass network. The Judd-Ofelt theory was successfully applied to characterize Ho3+ spectra of all the three glasses. From this theory various radiative properties, like transition probability A, branching ratio βr and the radiative lifetime τr, for 5S2 emission levels in the spectra of these glasses have been evaluated. The radiative lifetime for 5S2 level of Ho3+ ions has also been measured and quantum efficiencies were estimated. Among the three glasses studied the La2O3 mixed glass exhibited the highest quantum efficiency. The reasons for such higher value have been discussed based on the relationship between the structural modifications taking place around the Ho3+ ions.  相似文献   

12.
The effect of N2 treatment on the photocatalytic activity of Pt0/TiO2 was investigated. The results showed that after treatment at 500 °C in N2, 70% of the photocatalytic activity of 1.0 wt.% Pt0/TiO2 was lost by the evaluation of photocatalytic oxidation reaction of C3H6. Transmission electron microscopy (TEM) and Ar+ ion sputtering tests revealed that in the course of high-temperature N2 treatment, the size of Pt0 particles on TiO2 increases and a strong interaction between metal and support, i.e. Pt0 particles encapsulated by TixOy, happens, which are the reasons for the deactivation of Pt0/TiO2 photocatalyst treated by high-temperature N2.  相似文献   

13.
Rotationally resolved electronic spectrum of the origin band in the 2A″-X2A″ transition of a nonlinear carbon chain radical C6H4+ has been recorded in the 604 nm region using cw cavity ring down spectroscopy. The radical was produced by a discharge through an acetylene-helium mixture in a supersonic planar expansion. The rotational structure has been analysed and precisely determined. A band having a-type prolate rotational structure has also been observed near 581 nm. By considering the results of ab initio calculations this band is assigned to a transition involving the excitation of the ν12 fundamental in the upper 2A″ electronic state of the same C6H4+ isomer.  相似文献   

14.
The Ca2.95−yDy0.05B2O6:yNa+ (0≤y≤0.20) phosphors were synthesized at 1100 °C in air by the solid-state reaction route. The as-synthesized phosphors were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), photoluminescence excitation (PLE), photoluminescence (PL) spectra and thermoluminescence (TL) spectra. The PLE spectra show the excitation peaks from 300 to 400 nm due to the 4f-4f transitions of Dy3+. This mercury-free excitation is useful for solid-state lighting and light-emitting diodes (LEDs). The emission of Dy3+ ions on 350 nm excitation was observed at 480 nm (blue) due to the 4F9/26H15/2 transitions, 575 nm (yellow) due to 4F9/26H13/2 transitions and 660 nm (red) due to weak 4F9/26H11/2 emissions. The PL results from the investigated Ca2.95−yDy0.05B2O6:yNa+ phosphors show that Dy3+ emissions increase with the increase of the Na+ codoping ions. The integral intensity of yellow to blue (Y/B) can be tuned by controlling Na+ content. By the simulation of white light, the optimal CIE value (0.328, 0.334) can be achieved when the content of Na+-codoping ions is y=0.2. The results imply that the Ca2.95−yDy0.05B2O6:yNa+ phosphors could be potentially used as white LEDs.  相似文献   

15.
The kinetics and mechanisms of the reactions of cyanomidyl radical (HNCN) with oxygen atoms and molecules have been investigated by ab initio calculations with rate constant prediction. The doublet and quartet state potential energy surfaces (PESs) of the two reactions have been calculated by single-point calculations at the CCSD(T)/6-311+G(3df, 2p) level based on geometries optimized at the CCSD/6-311++G(d, p) level. The rate constants for various product channels of the two reactions in the temperature range of 300-3000 K are predicted by variational transition state and RRKM theories. The predicted total rate constants of the O(3P) + HNCN reaction at 760 Torr Ar pressure can be represented by the expressions ktotal (O + HNCN) = 3.12 × 10−10 × T−0.05 exp (−37/T) cm3 molecule−1 s−1 at T = 300-3000 K. The branching ratios of primary channels of the O(3P) + HNCN are predicted: k1 for producing the NO + CNH accounts for 0.72-0.64, k2 + k9 for producing the 3NH + NCO accounts for 0.27-0.32, and k6 for producing the CN + HNO accounts for 0.01-0.07 in the temperature range studied. Meanwhile, the predicted total rate constants of the O2 + HNCN reaction at 760 Torr Ar pressure can be represented by the expression, ktotal(O2 + HNCN) = 2.10 × 10−16 × T1.28exp (−12200/T) cm3 molecule−1 s−1 at T = 300-3000 K. The predicted branching ratio for k11 + k13 producing HO2 + 3NCN as the primary products accounts for 0.98-1.00 in the temperature range studied.  相似文献   

16.
Alkaline hexafluorostantanate red phosphors Na2SnF6:Mn4+ and Cs2SnF6:Mn4+ are synthesized by chemical reaction in HF/NaMnO4 (CsMnO4)/H2O2/H2O mixed solutions immersed with tin metal. X-ray diffraction patterns suggest that the synthesized phosphors have a tetragonal symmetry with the space group D4h14 (Na2SnF6:Mn4+) and a trigonal symmetry with the space group D3d3 (Cs2SnF6:Mn4+). Photoluminescence (PL) analysis, PL excitation (PLE) spectroscopy, and the Raman scattering techniques are used to investigate the optical properties of the phosphors. The Franck-Condon analysis of the PLE data yields the Mn4+-related optical transitions to occur at ∼2.39 and ∼2.38 eV (4A2g4T2g) and at ∼2.83 and ∼2.76 eV (4A2g4T1g) for Na2SnF6:Mn4+ and Cs2SnF6:Mn4+, respectively. The crystal field parameters (Dq) of the Mn4+ ions in the Na2SnF6 and Cs2SnF6 hosts are determined to be ∼1930 and ∼1920 cm−1, respectively. Temperature-dependent PL measurements are performed from 20 to 440 K in steps of 10 K, and the obtained results are interpreted by taking into account the Bose-Einstein occupation factor. Comprehensive discussion is given on the phosphorescent properties of a family of Mn4+-activated alkaline hexafluoride salts.  相似文献   

17.
The rotational spectrum of phosphaethene (CH2PH) was reinvestigated. One hundred and nineteen new lines were measured in the submillimeter range from 500 to 650 GHz. The determination of the centrifugal distortion constants is significantly improved. As the molecule is close to symmetric prolate top, both reduction A and S were compared. The equilibrium structure has been derived from experimental ground state rotational constants and ab initio rovibrational interaction parameters. This semi-experimental structure is in excellent agreement with the ab initio structure calculated at the CCSD(T) level of theory using a basis set of quintuple-zeta quality and a core correlation correction. The structure of CH2PH was compared to that of CH2NH which was also determined for this goal. It is found that the semi-experimental structure of CH2NH is less accurate than the ab initio structure. It is also found that the methylene group is much more asymmetric in CH2NH than in CH2PH.  相似文献   

18.
The high-resolution Fourier transform absorption spectrum of an isotopic sample of nitrogen dioxide, 15N16O2, was recorded in the 3.4 μm region. Starting from the results of a previous study [Y. Hamada, J. Mol. Struct. 242 (1991) 367-377] a new analysis of the ν1 + ν3 band located at 2858.7077 cm−1 has been performed. This new assignment concerns (1 0 1) energy levels involving rotational quantum numbers up to Ka = 10 and N = 54. Using a theoretical model which accounts for both the electron spin-rotation resonances within each vibrational state and the Coriolis interactions between the (1 2 0) and (1 0 1) vibrational states, the spin-rotation energy levels of the (1 0 1) vibrational state could be reproduced within their experimental uncertainty. In this way, the precise vibrational energy, rotational, spin-rotation, and coupling constants were achieved for the {(1 2 0), (1 0 1)} interacting states of 15N16O2. Using these parameters and the transition moment operator which was obtained for the main isotopic species, 14N16O2, a comprehensive list of the line positions and intensities was generated for the ν1 + ν3 band of 15N16O2.  相似文献   

19.
The electron spin resonance spectra (characterized by g factors g, g and hyperfine structure constants A and A) of Ba2Zn(HCOO)6(H2O) (BZFA): VO2+ crystal are calculated from high order perturbation formulas. The calculated results are in good agreement with the observed values. The local structure parameters of [VO(H2O)5]2+ clusters are also obtained from the calculation. The magnitudes of the metal-ligand distances parallel and perpendicular to the C4-axis are, respectively, R≈0.163 nm and R≈0.210 nm. It is shown that the local structure around the V4+ ion possesses a compressed tetragonal distortion along C4-axis.  相似文献   

20.
The absorption spectrum of ozone, 16O3, has been recorded in the 5903-5960 cm−1 region by high sensitivity CW-cavity ring down spectroscopy (αmin ∼ 5 × 10−10 cm−1). The ν1 + 3ν2 + 3ν3 and 4ν1 + ν2 + ν3 A-type bands centred at 5919.15 and 5947.07 cm−1 were newly observed. A set of 173 and 168 energy levels could be experimentally determined for the (1 3 3) and (4 1 1) states, respectively. Except for a few Ka = 5 levels of the (4 1 1) state, the rotational structure of the two states was found mostly unperturbed. The spectroscopic parameters were determined from a fit of the corresponding line positions by considering the (1 3 3) and (4 1 1) states as isolated. The determined effective Hamiltonian and transition moment operators were used to generate a list of 785 transitions given as Supplementary Material.  相似文献   

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