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1.
Emission spectra of SrH and SrD have been studied at high resolution using a Fourier transform spectrometer. The molecules have been produced in a high temperature furnace from the reaction of strontium metal vapor with H2/D2 in the presence of a slow flow of Ar gas. The spectra observed in the 18 000–19 500 cm?1 region consist of the 0–0 and 1–1 bands of the E2Π–X2Σ+ transition of the two isotopologues. A rotational analysis of these bands has been obtained by combining the present measurements with previously available pure rotation and vibration–rotation measurements for the ground state, and improved spectroscopic constants have been obtained for the E2Π state. The present analysis provides spectroscopic constants for the E2Π state as ΔG(½) = 1166.1011(15) cm?1, Be = 3.805503(32) cm?1, αe = 0.098880(47) cm?1, re = 2.1083727(89) Å for SrH, and ΔG(½) = 839.1283(23) cm?1, Be = 1.918564(15) cm?1, αe = 0.034719(23) cm?1, re = 2.1121943(83) Å for SrD.  相似文献   

2.
3 MeV electron irradiation induced-defects in CuInSe2 (CIS) thin films have been investigated. Both of the carrier concentration and Hall mobility were decreased as the electron fluence exceeded 1×1017 cm−2. The carrier removal rate was estimated to be about 1 cm−1. To evaluate electron irradiation-induced defect, the electrical properties of CIS thin films before and after irradiation were investigated between 80 and 300 K. From the temperature dependence of the carrier concentration in non-irradiated thin films, we obtained ND=1.8×1017 cm−3, NA=1.7×1016 cm−3 and ED=18 meV from the SALS fitting to the experimental data on the basis of the charge balance equation. After irradiation, a new defect level was formed, and NT0=1.4×1017 cm−3 and ET=54 meV were also obtained from the same procedure. From the temperature dependence of Hall mobility, the ionized impurity density was discussed before and after the irradiation.  相似文献   

3.
The absorption spectrum of nitrous oxide, N2O, has been recorded by CW-Cavity Ring Down Spectroscopy between 6950 and 7653 cm?1. The spectra were obtained at Doppler limited resolution using a CW-CRDS spectrometer based on a series of fibered DFB laser diodes. The typical noise equivalent absorption, in the order of αmin≈1×10?10 cm?1, allowed for the detection of lines with intensity as small as 1×10–29 cm/molecule.The positions of 7203 lines of four isotopologues (14N216O, 14N15N16O, 15N14N16O and 14N218O) were measured with a typical accuracy of 1.0×10?3 cm?1. The transitions were rovibrationally assigned on the basis of the global effective Hamiltonian models developed for each isotopologue. The band by band analysis allowed for the determination of the rovibrational parameters of more than 95 bands, most of them being newly reported while new rotational transitions are measured for the others. The measured line positions of the main isotopologue are found to be in good agreement with the predictions of the effective Hamiltonian model but a few deviations up to 0.20 cm?1 are observed. Local rovibrational perturbations were evidenced for several bands. The interaction mechanisms and the perturbers were univocally assigned on the basis of the effective Hamiltonian models.  相似文献   

4.
《Solid State Ionics》2006,177(19-25):1619-1624
The kinetics of the electrochemical reduction of molecular nitrogen at gold micro electrodes on yttria stabilized zirconia (YSZ) solid oxide electrolyte is studied by steady state polarization measurements. From the η / lg i plot for both cathodic and anodic polarization the apparent transfer coefficients αa and αc are evaluated. The sum of αa + αc exceeds unity and thus a multistep electron transfer process is suggested. The concept of the stoichiometric number is applied to the electrode reaction N2 + 6e = 2N3− supposing that the overall process involves at least two intermediate species. On the basis of the evaluation of the experimental results the reaction N2 + e  N22− is suggested as the rate determining reaction step for the cathodic nitrogen reduction and nitride formation.  相似文献   

5.
The luminescence kinetics of CsI(Tl) exposed to an electron pulse irradiation (Ee = 250 keV, t1/2 = 10 ns, j = 2 ÷ 160 mJ/cm2) has been studied. It has been discovered that the slow emission rise is due to hole Vk–Tl0 recombination luminescence at temperature from 100 to 160 K and electron–VkA recombination, where electrons released from single Tl0 at temperature from 180 to 300 K. The effect of Tl concentration on both processes has been investigated.  相似文献   

6.
Ni-containing anode is currently used with many electrolytes of solid oxide fuel cells (SOFCs). However, Ni is easily oxidized and deteriorates the LaGaO3-based electrolyte. A La-doped SrTiO3 (LST, La0.2Sr0.8TiO3) is a candidate as an anode material to solve the Ni poisoning problem in LaGaO3-based SOFC. In this study, a single-phase LST and an LST-Gd0.2Ce0.8O2 ? δ (GDC) composite were tested as the possible anodes on La0.9Sr0.1Ga0.8Mg0.2O3 ? δ (LSGM) electrolyte. In order to further improve the anodic performance, Ni was impregnated into the LST-GDC composite anode. The performance was examined from 600 °C to 800 °C by measuring impedance of the electrolyte-supported, symmetric (anode/electrolyte/anode) cells. A polarization resistance (Rp) of LST-GDC anode was much reduced from that of LST anode. When Ni was impregnated into LST-GDC composite, the Rp value was further reduced to ~ 10% of the single-phase LST anode, and it was 1 Ωcm2 at 800 °C in 97% H2 + 3% H2O atmosphere. A single cell with Ni-impregnated LST-GDC as an anode, Ba0.5Sr0.5Co0.8Fe0.2O3 ? δ (BSCF) as a cathode and LSGM as an electrolyte exhibited the maximum power density of 275 mW/cm2 at 800 °C, increased from ~ 60 mW/cm2 for the cell using the LST-GDC as an anode. Thus, LST-GDC composite is promising as a component of anode.  相似文献   

7.
In our effort to systematically study the far infrared (FIR) spectra of asymmetrically mono deuterated methanol (CH2DOH) and thereby obtain the transition wavenumbers with better and better accuracy (Mukhopadhyay, 2016a,b), the complete Fourier transform (FT) spectra from FIR to infrared (IR) vibrational bands (in the range 50–1190 cm−1) have been re-recorded using the Synchrotron Radiation Source at the Canadian Light Sources in Saskatchewan, Canada. The resolution of the spectrum is unprecedented, reaching beyond the Doppler limited resolution as low as about 0.0008 cm−1 with a signal to noise (S/N) ratio is many fold better than that can be obtained by commercially available FT spectrometer using thermal sources (e.g., Globar). Spectra were also recorded beyond 1190 cm−1 to about 5000 cm−1 at a somewhat lower resolution of 0.002–0.004 cm−1. In this report the analysis of the b-type and c-type torsional - rotational spectra in the ground vibrational state corresponding to gauche- (e1/o1) to gauche- (e1/o1) and gauche- (e1/o1) to trans- (e0) states in the ground vibrational state are reported and an atlas of the wavenumber for about 2500 FIR assigned absorption lines has been prepared. The transitions within a given sub-band are analyzed using state dependent expansion parameters and the Q-branch origins. The data from previous results (Mukhopadhyay, 2016a,b) along with the present work allowed a global analysis yielding a complete set of molecular parameters. The state dependent molecular parameters reproduce the experimental wavenumbers within experimental uncertainty. In addition, the sensitivity of the spectrum allowed observation of forbidden transitions previously unobserved and helped reassignment of rotational angular momentum quantum numbers of some ΔK = ±1, Q-branch transitions in highly excited states recently reported in the literature. To our knowledge the wavenumbers reported in the present work are the most accurate so far reported in the literature and represent the highest resolution spectra for this molecular species.  相似文献   

8.
Using three-dimensional classical ensembles, we have investigated the enhancement of double ionization of perpendicularly aligned H2 molecules by a 800 nm laser pulse with intensity ranging from 1 × 1014 W/cm2 to 6 × 1014 W/cm2. The simulated results show that double ionization probability of H2 strongly depends on R and reaches a maximum at an intensity independent critical distance RC  5 a.u. Furthermore, the enhancement of double ionization is more pronounced in the cases of weaker or stronger fields. These results, a well indication of the influence of molecular structures and laser–molecule interactions on double ionization of diatomic molecules, are analyzed in detail and qualitatively explained based on the field-induced barrier suppression model and back analysis.  相似文献   

9.
The first high-resolution absorption spectrum of the 5ν3 band of the 14N16O2 molecule at 7766.071 cm?1 was recorded by high sensitivity CW-Cavity Ring Down Spectroscopy between 7674 and 7795 cm?1. The noise equivalent absorption of the recordings was αmin≈1×10?10 cm?1. The assignments involve energy levels of the (0,0,5) vibrational state with rotational quantum numbers up to Ka=9 and N=47. The set of the spin–rotation energy levels were reproduced within their experimental uncertainty using a theoretical model, which takes explicitly into account the Coriolis interactions between the spin rotational levels of the (0,0,5) vibrational state and those of the (0,2,4) dark state together with the electron spin–rotation resonances within the (0,0,5) and (0,2,4) states. Precise values were determined for the (0,0,5) vibrational energy rotational, spin-rotational constants and for the (0,2,4)?(0,0,5) coupling constants. In addition the (0,2,4) rotational and spin-rotational constants were estimated. Using these parameters and the value of the transition dipole moment operator determined from a fit of a selection of experimental line intensities, the synthetic spectrum of the 5ν3 band was generated and is provided as Supplementary material.  相似文献   

10.
《Solid State Ionics》2009,180(40):1683-1689
The complex perovskite (Pr0.75Sr0.25)1  xCr0.5Mn0.5O3  δ (PSCM) has been prepared and studied as possible anode material for high-temperature solid oxide fuel cells (SOFCs). PSCM exhibits GdFeO3-type structure and is both physically and chemically compatible with the conventional YSZ electrolyte. The reduction of PSCM resulted in structural change from orthorhombic Pbnm to cubic Pm-3m. Selected area electron diffraction (SAED) analysis on the reduced phases indicated the presence of a √2 × √2 × 2 superlattice. The total conductivity values of ∼ 75% dense Pr0.75Sr0.25Cr0.5Mn0.5O3  δ at 900 °C in air and 5% H2/Ar are 9.6 and 0.14 S cm 1 respectively. The conductivity of PSCM drops with decreasing Po2 and is a p-type conductor at all studied Po2. The average TEC of Pr0.75Sr0.25Cr0.5Mn0.5O3  δ is 9.3 × 10 6 K 1, in the temperature range of 100–900 °C and is close to that of YSZ electrolyte. The anode polarization resistance of PSCM in wet 5%H2 is 1.31 Ω cm2 at 910 °C and in wet CH4 at 930 °C; the polarization resistance is 1.29 Ω cm2. PSCM was unstable at 900 °C in unhumidified hydrogen. Cell performance measurements carried out using graded PSCM and La0.8Sr0.2MnO3 as anode and cathode respectively yielded a maximum power density of 0.18 W cm 2 in wet 5%H2/Ar at 910 °C and the corresponding current density was 0.44 A cm 2 at 0.4 V. The activation energy for the electrochemical cell operating in wet (3% H2O) 5%H2/Ar fuel is 85 kJ mol 1.  相似文献   

11.
The infrared (IR) spectra corresponding to OCD bending vibration of asymmetrically deuterated methanol species CH2DOH have been recorded with a Fourier Transform Spectrometer. The spectrum shows a typical structure of a parallel a-type band. This is expected because the bending vibration mainly executed parallel to the symmetry axis The Q-branch lines are grouped closely around 896 cm−1 and the P- and R-Branches show complex structure. Nonetheless it was possible to assign a-type P- and R-branch lines up to K value of 8 and J value up to about 20 in most cases. The Q-branch lines for higher K values can be followed to about J = 15, the presence of which confirmed the assignments. The observations suggest that in the OCD bend some energy levels are highly interacted by highly excited torsional state from the ground torsional state. A full catalogue is presented along with the effective molecular parameters. An intensity anomaly was also observed in the transitions. So far it has been possible to assign only transitions between e0  e0 states. Plausible explanations of intensity anomaly are presented. Lastly, a number of optically pumped far infrared (FIR) laser lines have been assigned either to exact or tentative quantum states. These assignments should prove valuable for production of new FIR laser lines.  相似文献   

12.
《Solid State Ionics》2006,177(13-14):1117-1122
We report a comparative study of transport and thermodynamic properties of single-crystal and polycrystalline samples of the ionic salt CsH5(PO4)2 possessing a peculiar three-dimensional hydrogen-bond network. The observed potential of electrolyte decomposition ≈ 1.3 V indicates that the main charge carriers in this salt are protons. However, in spite of the high proton concentration, the conductivity appears to be rather low with a high apparent activation energy Ea  2 eV, implying that protons are strongly bound. The transport anisotropy though is not large, correlates with the crystal structure: the highest conductivity is found in the [001] direction (σ130 °C 5.6 × 10 6 S cm 1) while the minimal conductivity is in the [100] direction (σ130 °C 10 −6 S cm 1). The conductivity of polycrystalline samples appears to exceed the bulk one by 1–3 orders of magnitude with a concomitant decrease of the activation energy (Ea  1.05 eV), which indicates that a pseudo-liquid layer with a high proton mobility is formed at the surface of grains. Infrared and Raman spectroscopy used to study the dynamics of the hydrogen-bond system in single-crystal and polycrystalline samples have confirmed the formation of such a modified surface layer in the latter. However, no bulk phase transition into the superionic disordered phase is observed in CsH5(PO4)2 up to the melting point Tmelt 151.6 °C, in contrast to its closest relative compound CsH2PO4.  相似文献   

13.
The effect of pulse amplitude on the ferroelectric and switching properties of pulsed laser deposited Ba0.8Sr0.2TiO3 thin films has been studied. The structural and morphological analysis revealed that the films had a well crystallized perovskite phase and grain size of about 30–40 nm. A well saturated P–E hysteresis loop was observed with a remnant polarization (Pr)  4.8 μC/cm2 and a coercive field  100 kV/cm at a frequency of 1 kHz. The Pr has been found to be decreased only 4.3% after passing 8.0 × 108 cycles. The analysis of switching response with nucleation limited switching model reveals that characteristic switching time (t0) variance is due to the random distribution of the local electric fields. The peak value of polarization current and t0 exhibits exponential dependence on reciprocal of pulse amplitude.  相似文献   

14.
A simple method of deriving effective demagnetizing factors (Nxe,Nye) for the use of Kittel's ferromagnetic resonance formula is reported. The effective demagnetizing factors are expressed by an anisotropy energy (G) and a static field direction (θ,φ). By this derivation method, the resonance equations of thin films having a uniaxial or a four-fold anisotropy are obtained when a static field is rotated in the film plane. Six arrangements are calculated: (1) perpendicular anisotropy, (2) in-plane anisotropy, (3) cubic-crystal (0 0 1) face, (4) cubic-crystal (0 1 1) face, (5) cubic-crystal (1 1 1) face, and (6) oblique anisotropy films.  相似文献   

15.
C. Rohmann  J.B. Metson  H. Idriss 《Surface science》2011,605(17-18):1694-1703
The adsorption of CO on α-Al2O3(0001) was studied using the DFT-GGA computational method and on α-Al2O3 powder experimentally by Infra red spectroscopy. The core and valence level regions of α-Al2O3(0001) single crystal surface were also studied experimentally. Ar ions sputtering of the surface results in a slight but reproducible decrease in the XPS O2p lines in the valence band regions due to preferential removal of surface (and near surface) O atoms. Core level XPS O1s and Al2p further confirmed oxygen depletion with an associated surface stoichiometry close to Al2O2.9. The adsorption energy of CO was computed and found equal to 0.52 eV for θ = 0.25, it decreased to 0.42 eV at θ = 1. The IR frequency of νCO was also computed and in all cases it was blue shifted with respect to gas phase CO. The shift, Δν, decreased with increasing coverage where it was found equal to 56 cm? 1 for θ = 0.25 and decreased to 30 cm? 1 for θ = 1. Structural analyses indicated that the change in the adsorption energy and the associated frequency shift is due to surface relaxation upon adsorption. Experimentally the adsorption of CO gave rise to one main IR peak at 2154 cm? 1 at 0.3 Torr and above. Two far smaller peaks are also seen at lower pressures of 0.03–0.2 Torr at 2189 and 2178 cm? 1. The isosteric heat of adsorption was computed for the IR band at 2154 cm? 1 and was found equal to 0.2 eV which did not change with coverage in the investigated range up to θ = 0.6.  相似文献   

16.
We fabricated a heavily Bi-doped (xBi  2 × 1019 cm−3) PbTe p–n homojunction diode that detects mid-infrared wavelengths by the temperature difference method (TDM) under controlled vapor pressure (CVP) liquid phase epitaxy (LPE). The photocurrent density produced by the heavily Bi-doped diode sample is approximately 20 times and 3 times greater than that produced by an undoped and heavily In-doped sample, respectively. By varying the ambient temperature from 15 K to 225 K, the detectable wavelength is tunable from 6.18 μm to 4.20 μm. The peak shift of the detectable wavelength is shorter in the heavily Bi-doped sample than in the undoped sample, consistent with our previously proposed model, in which Bi–Bi nearest donor–acceptor pairs are formed in the heavily Bi-doped PbTe liquid phase epitaxial layer. Current–voltage (IV) measurements of the heavily Bi-doped diode sample under infrared exposure at 77 K indicated a likely leak in the dark current, arising from the deeper levels. From the dark IV measurements, the activation energy of the deep level was estimated as 0.067 eV, close to the energy of the deep Tl-doped PbTe acceptor layer. We conclude that the deep level originates from the Tl-doped p-type epitaxial layer.  相似文献   

17.
Glasses in the system xFe2O3·(100?x) [45ZnO·55B2O3] (0≤x≤10 mol%) have been prepared by melting at 1200 °C and rapidly cooling at room temperature. The obtained samples were submitted to an additional thermal treatment at 570 °C for 12 h in order to relax the glass structure as well as to improve the local order. The as cast and heat treated samples were investigated using X-ray diffraction (XRD) and electron paramagnetic resonance (EPR) measurements. The XRD patterns of all the studied samples show their vitreous nature. Structural modifications occurring in the heat treated samples compared to the untreated ones have been pointed out. EPR spectra of untreated and heat treated samples revealed resonance absorptions centered at g≈2.0, g≈4.3 and g≈6.4. The compositional variation of the line intensity and linewidth of the absorptions from g≈4.3 and g≈2.0 have been interpreted in terms of the variation in the concentration of the Fe3+ ions and the interaction between the iron ions. The EPR spectra of the untreated samples containing 5 mol% Fe2O3 have been studied at different temperatures (110–290 K). The line intensity of the resonance signals decreases with increase in temperature whereas the linewidth is found to be independent of temperature. It was also found that the temperature variation of reciprocal line intensity obeys the Boltzmann law.  相似文献   

18.
《Solid State Ionics》2006,177(1-2):95-104
The plastic crystal phase forming N-methyl-N-propylpyrrolidinium tetrafluoroborate organic salt (P13BF4) was combined with 2, 5 and 10 wt.% poly(vinyl pyrrolidone) (PVP). The ternary 2 wt.% PVP/2 wt.% LiBF4/P13BF4 was also investigated. Thermal analysis, conductivity, optical thermomicroscopy, and Nuclear Magnetic Resonance (11B, 19F, 1H, 7Li) were used to probe the fundamental transport processes. Both the onset of phase I and the final melting temperature were reduced with increasing additions of PVP. Conductivity in phase I was 2.6 × 10 4 S cm 1 5.2 × 10 4 S cm 1 1.1 × 10 4 S cm 1 and 3.9 × 10 5 S cm 1 for 0, 2, 5 and 10 wt.%PVP/P13BF4, respectively. Doping with 2 wt.% LiBF4 increased the conductivity by up to an order of magnitude in phase II. Further additions of 2 wt.% PVP slightly reduced the conductivity, although it remained higher than for pure P13BF4.  相似文献   

19.
We demonstrated efficient red organic light-emitting diodes based on a wide band gap material 9,10-bis(2-naphthyl)anthracene (ADN) doped with 4-(dicyano-methylene)-2-t-butyle-6-(1,1,7,7-tetramethyl-julolidyl-9-enyl)-4H-pyran (DCJTB) as a red dopant and 2,3,6,7-tetrahydro-1,1,7,7,-tetramethyl-1H,5H,11H-10(2-benzothiazolyl)quinolizine-[9,9a,1gh]coumarin (C545T) as an assistant dopant. The typical device structure was glass substrate/ITO/4,4′,4″-tris(N-3-methylphenyl-N-phenyl-amino)triphenylamine (m-MTDATA)/N,N′-bis(naphthalene-1-yl)-N,N′-diphenyl-benzidine (NPB)/[ADN:Alq3]:DCJTB:C545T/Alq3/LiF/Al. It was found that C545T dopant did not by itself emit but did assist the energy transfer from the host (ADN) to the red emitting dopant via cascade energy transfer mechanism. The OLEDs realized by this approach significantly improved the EL efficiency. We achieved a significant improvement regarding saturated red color when a polar co-host emitter (Alq3) was incorporated in the matrix of [ADN:Alq3]. Since ADN possesses a considerable high electron mobility of 3.1 × 10−4 cm2  V−1 s−1, co-host devices with high concentration of ADN (>70%) exhibited low driving voltage and high current efficiency as compared to the devices without ADN. We obtained a device with a current efficiency of 3.6 cd/A, Commission International d’Eclairage coordinates of [0.618, 0.373] and peak λmax = 620 nm at a current density of 20 mA/cm2. This is a promising way of utilizing wide band gap material as the host to make red OLEDs, which will be useful in improving the electroluminescent performance of devices and simplifying the process of fabricating full color OLEDs.  相似文献   

20.
《Solid State Ionics》2006,177(11-12):1091-1097
The effects of compositions on properties of PEO/KI/I2 salts polymer electrolytes were investigated to optimize the photovoltaic performance of solid state DSSCs. XRD pattern for the mole ratio 12:1 of [EO:KI] was showed the formation of complete amorphous complex. DSC results also confirmed the amorphous nature of the polymer electrolyte. The highest value of ionic conductivity is 8.36 × 10 5 S/cm at 303 K (ambient temperature) and 2.32 × 10 4 S/cm at 333 K (moderate temperature) for the mole ratio 12:1 of EO:KI complex. The effect of contribution of [I] and [I3] concentration with conductivity were also evaluated. FTIR spectrum reveals that the alkali metal cations were co-ordinated to ether oxygen of PEO. The formation of polyiodide ions, such as symmetric I3 (114 cm 1) and I5 (145 cm 1) caused by the addition of iodine was confirmed by FT Raman spectroscopic measurements. The optimum composition of PEO–KI–I2 polymer electrolyte system for higher conductivity at ambient and moderate temperatures was reported. A linear Arrhenius type behaviour was observed for all the PEO–KI polymer complexes. Transport number measurements were carried out for several polymer electrolyte compositions. Dye-sensitized solar cells were fabricated by using higher conductivity polymer electrolyte compositions and its photoelectrochemical performance was investigated. The fill factor, short-circuit current, photovoltage and energy conversion efficiency of the DSSC assembled with optimized electrolyte composition were calculated to be 0.563, 6.124 mA/cm2, 593 mV and 2.044% respectively.  相似文献   

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