Effects of hydrogen flow on properties of hydrogen doped ZnO thin films prepared by RF magnetron sputtering

The hydrogen doped ZnO (ZnO:H) thin films were deposited on quartz glass substrates by radio frequency magnetron sputtering. The doping characteristics of ZnO:H thin films with varied hydrogen flow ratio were investigated. At low hydrogen flow ratio (H₂/(H₂+Ar)≤0.02), the ZnO:H thin films exhibited dominant (002) peaks from X-ray diffraction and the lattice constants became smaller. The particles were mainly a columnar structure. The particles’ size became smaller, and the island-like structure appeared on the thin films surface. In addition, the low resistivity properties of ZnO:H thin films was ascribed to the increase of the carriers concentration and carriers mobility; When the hydrogen flow ratio was more than 0.02 (M≥0.02), two absorption bands at 1400–1800 cm^?1 and 3200–3900 cm^?1 were observed from the FT-IR spectra, which indicated that the ZnO:H thin films had typical Zn–H bonding, O–H bonding (hydroxyl), and Zn–H–O bonding (like-hydroxyl). The scanning electron microscope (SEM) results show that a large number of hydroxyl agglomeration formed an island-like structure on the thin films surface. The absorption peak at about 575 cm^?1 in the Raman spectra indicated that oxygen vacancies (V_O) defects were produced in the process of high hydrogen doping. In this condition, the low resistivity properties of ZnO:H thin films were mainly due to the increasing electron concentration resulted from V_O. Meanwhile, the Raman absorption peaks at approximately 98 cm^?1 and 436 cm^?1 became weaker, and the (002) XRD diffraction peak quenched and the lattice constants increased, which shows that the ZnO:H thin films no longer presented a typical ZnO hexagonal wurtzite structure. With the increasing of hydrogen flow ratio, the optical transmittance of ZnO:H thin films in the ultraviolet band show a clear Burstein–Moss shift effect, which further explained that electron concentration was increased due to the increasing V_O with high hydrogen doping concentration. Moreover, the optical reflectance of the thin films decreased, indicating the higher roughness of the films surface. It was noteworthy that etching effect of H plasma was obvious in the process of heavy hydrogen doping.     

Absorption spectra of Cu2+ in azurite

EPR and optical absorption studies in azurite have been carried out at room and low temperatures. The EPR spectrum reveals that the ground state for Cu²⁺ ion is ²B₁. Peak to peak linewidth of EPR spectrum is calculated (ΔH_p = 76 G) and found to be close with the observed value. The Cu²⁺ ion situated in D_4h symmetry with spin-orbit interaction exhibits bands at 11,806, 16,484, 17,952 and 19,793 cm^?1. The tetragonal field parameters are calculated to be Ds = ? 3364 cm^?1 and Dt = ? 604 cm^?1. The crystal field splitting parameter is found to be Dq = ? 1175 cm^?1.     

Absorption spectra of C6H6 and C6D6 near 340 nm

The absorption spectra of C₆H₆ and C₆D₆ in the liquid phase have been studied near 340 nm. The absorption spectrophotometric mounting was a sequential double-beam attachment with linear response to energy on scanning of the spectrum before the exit slit and an electronic device which gives directly either the absorbance or the integrated absorbance of a transition and, consequently, its oscillator strength.The oscillator strength measured for the band of C₆H₆ is 8×10^?8, which corresponds to a dipole moment of 2.4×10^?3 Debye; this value is of the same order as a theoretical value calculated by Tsubomura and Mulliken (3.8×10^?3 Debye) for a transition between states ³F and ³A of an oxygen-benzene pair. This agreement corroborates the hypothetical existence of such a transition.The first vibrational band is at 28553 cm^?1 for C₆H₆; this band is not observed in the vapor or solid phase. It corresponds probably to the transition 0-0, which is considered in the literature to be near 29500 cm^?1. The isotopic shift measured for this first band is 164 cm^?1. The vibrational frequencies are, respectively, 910 cm^?1 for C₆H₆ and 889 cm^?1 for C₆D₆.     

Far-infrared absorption spectra of water vapor H216O and isotopic modifications

Far-infrared absorption spectra of H₂¹⁶O, H₂¹⁸O, H¹⁶OD, H¹⁸OD, D₂¹⁶O, D₂¹⁸O have been observed between 10 and 40 cm^?1 at a resolution of 0.07 cm^?1. Experimental and calculated line positions agree within the accuracy of the experiment (±0.003 cm^?1). The relative intensities of type a and type b transitions of H¹⁶OD and H¹⁸OD are used to estimate the ratio $\text{μ}{}_{\mathrm{a}}\text{μ}{}_{\mathrm{b}}$.     

Potential models and local mode vibrational eigenvalue calculations for acetylene

Two potential models for acetylene are developed and tested by comparison between variational calculations for the stretching vibrational term values and available spectroscopic data. The first model based on local bond potentials with harmonic interbond coupling gives root mean square deviations of 6 cm^?1 for C₂H₂ and 3 cm^?1 for C₂D₂. The second model is more ambitious, being designed to reproduce the dissociation characteristics of the molecules, and the calculated root mean square deviations from the experimental vibrational term values are larger, 32 cm^?1 for C₂H₂ and 24 cm^?1 for C₂D₂. The eigenvalue spectrum of C₂H₂ is shown to differ from that of C₂D₂ in showingmarked local mode features and this difference in behaviour is underlined by means of a correlation diagram. Finally it is shown how the known normal mode frequencies and anharmonic constants may be introduced into a simple model in order to predict the excited term values of C₂H₂, again with a root mean square deviation of 6 cm^?1.     

Near and far infrared vibrational absorption ofH i − andD i − centres in KBr

Near infrared absorption measurements by Gross and Bron led to the suggestion that the threefold degeneracy of the localized vibration ofH _i ^? andD _i ^? centres in KI is completely lifted in KBr. Using thermal annealing procedures,H _i ^? -D _i ^? substitution and far infrared techniques we found that the lines at 794, 840, and 896 cm^?1 cannot be interpreted as a splitting of the main line. Only the 794 cm^?1 line can be correlated with the direct excitation of theH _i ^? oscillator. The absence of any splitting in this line (its halfwidth at 9 °K is only 1.5 cm^?1) indicates that also in KBrH _i ^? centres have at most only slightly perturbedT _d symmetry.     

An experimental study of the collisional broadening of the Na-D lines by Ar and N2 perturbers in flames and vapor cells—II. The line wings

In this paper, we report on measurements of the fluorescence-excitation profile of the red Na-D₁ line wing from about 1 cm^?1 to 1100 cm^?1 and of the blue Na-D₂ line-wing from about 1 cm^?1 to 600 cm^?1, with respect to the corresponding line centre. We have also measured the fluorescence-excitation profile of the red Na-D₂ and blue Na-D₁ inner (overlapping) line wings from 1 cm^?1 with respect to the centre of each of the lines. All these wings were measured in several premixed, laminar, shielded H₂O₂Ar and H₂O₂N₂ flames at 1 atm (1400 K ? T ? 2300 K). We also measured these wings in a vapor cell containing Ar or N₂ perturbers (T ～ 480 K, p ～ 0.4 atm) in order to determine the influence of temperature on these wings. Using a tunable CW dye laser as excitation source, we determined the fluorescence-excitation profiles by measuring the total fluorescence intensity while tuning the laser wavelength. In order to specify the contributions that the different kinds of major flame perturbers (Ar, N₂, H₂O) make to the wings, we compared the wing profiles measured in various flames of different flame-gas compositions. In this comparison, the wing profiles were normalized with respect to the line-centre. We compared our measurements of far red Na-D₁ and blue Na-D₂ line-wings ($\text{Δσ ? 30}\text{cm}{}^{\mathrm{?1}}$) specified to Ar perturbers (at T = 500 K and T = 2000 K) with the results derived from quasi-static theory using available interaction potential data. In the case of Ar perturbers at T = 500 K, we observed a satellite at about 8 cm^?1 from the line-centre on the red Na-D₁ wing: this satellite was absent at T = 2000 K. The position of this red satellite was explained with the help of a set of “modified” potentials, which were constructed for interpreting the collisional Na-D broadening- and shift-rates deduced from our line-core observations and which were reported in Part I of this paper.     

Infrared absorptivity of the 9.6 μm ozone band as a function of spectral resolution and abundance

The i.r. absorptivity of the R-branch maximum (9.48 μm) of gaseous ozone was determined at 25°C as a function of spectral resolution and absorbance a/a total pressure of 735 torr of dry air. Ozone samples produced by a high voltage discharge in oxygen, and measured accurately by either a pressure or volume change, were spectroscopically measured in a 57741. environmental chamber at paths up to 69.17 m. A linear relation between spectral slit (Δv) and the ratio of the absorbances (R_v/p) of the observed absorption minimum between the R and Q branches to the absorption maximum of the R-branch was found for cm^-1 < Δv < 10cm^-1 and for absorption up to 48%. The i.r. absorptivity varied approx. 20% (from 3.9 to 4.8 cm^-1 STP) over the range of values for R_v/p studied. Absorptivity was weakly dependent on ozone abundance (w) for w?0.03 cm STP.     

Diffusionskonstante und charakteristische Absorption vor der Bandkante von Mn in ZnO-Kristallen

ZnO single crystals were doped with Mn and Co by diffusion. In the temperature range from 1400–1600 K the Mn and Co-diffusion-constants were determined:D _Mn=3.2 · 10^?3 exp (?2.87 eV/kT) cm² sec^?1 andD _Co=1·10exp(?3.98 eV/kT) cm² sec^?1. The Mn doped ZnO crystals show a characteristic colour due to an absorption near the intrinsic absorption edge. The corresponding absorption spectra were measured forE⊥c andE∥c. A discussion of different absorption mechanism shows that a charge-transfer transition is responsible for this absorption.     

Rotational analysis of the 5350 Å band of iodine by means of Fourier transform spectroscopy

We have recorded the 5350 Å (30, 0) band of the iodine spectrum with high resolution by means of Fourier transform spectroscopy. The rotational lines in the P and R branches were measured to J = 165 with reference to uranium standards emitted by a hollow cathode. The differences between the two sets of measurements were less than 0.001 cm^?1, and the standard deviation between the observed wavenumbers and those calculated with the spectroscopic constants B_v, D_v, and H_v is 0.0007 cm^?1. The precision reached is an order of magnitude greater than in previously published data, and the constants H_v of the iodine absorption spectrum have been determined for the first time. This work shows that the use of Fourier transform spectroscopy is particularly powerful for molecular absorption studies in the visible region where, although the multiplex gain is lost, the throughput gain remains, and this enables the performance to approach that achieved in the infrared. This method can be expected to open up not only significant new spectroscopic experiments, but it also allows a complete high-precision remeasurement of the existing molecular spectra in the visible and uv (electronic rotational-vibrational transitions).     

Analysis of the 2ν3 band of 12CD3F at 5.06 μm recorded under high resolution

The 2ν₃(A₁) band of ¹²CD₃F near 5.06 μm has been recorded with a resolution of 20–24 × 10^?3 cm^?1. The value of the parameter (α^B ? α^A) for this band was found to be very small and, therefore, the K structure of the R(J) and P(J) manifolds was unresolved for J < 15 and only partially resolved for larger J values. The band was analyzed using standard techniques and values for the following constants determined: ν₀ = 1977.178(3) cm^?1, B″ = 0.68216(9) cm^?1, D″_J = 1.10(30) × 10^?6 cm^?1, α^B = (B″ ? B′) = 3.086(7) × 10^?3 cm^?1, and β^J = (D″_J ? D′_J) = ?3.24(11) × 10^?7 cm^?1. A value of α^A = (A″ ? A′) = 2.90(5) × 10^?3 cm^?1 has been obtained through band contour simulations of the R(J) and P(J) multiplets.     

Ethane spectrum between 1940 and 2152 cm−1: Ground state parameters

The absorption spectrum of ethane was recorded between 1940 and 2152 cm^?1 at a resolution of 0.025 cm^?1. Ground state parameters were determined from the principal band in this region, ν₉ + ν₁₂(E_u): B₀ = 0.6630353 cm^?1, D₀^J = 1.0406 × 10^?6 cm^?1, D₀^JK = 2.575 × 10^?6 cm^?1 (standard errors are 7, 8, and 13, respectively, in the last digits quoted). The quoted values are from the analyses of 269 ground state combination differences, the standard deviation of the least-squares analysis was 0.0032 cm^?1.     

Improved potential energy curve and vibrational energies for the electronic ground state of the hydrogen molecule

The potential energy curve for the electronic ground state of the hydrogen molecule has been recomputed for intermediate and large internuclear separations. for 2.4 ≤ R ≤ 8.0a.u. the previous potential energy curve has been improved. The largest improvement amounts to 5.5 cm^?1, and was obtained in the vicinity of R = 4.4a.u.. Using the new potential energy curve, and the adiabatic and relativistic corrections, the vibrational and rotational energy levels have been calculated for H₂, HD, and D₂. The deviations of the calculated energy levels G(v) of H₂ and D₂ from the observed values follow very closely the nonadiabatic corrections resulting from the Van Vleck formula.     

中子辐照含氢FZ-Si的红外吸收研究

对于中子辐照的n-FZSi(H₂),利用红外吸收光谱研究了由于辐照所产生的各种与氢有关的缺陷态。在未辐照的样品和辐照的样品中分别发现了未曾报道的1992cm^{-1和1857cm-1吸收峰。对于在n-FZSi(H₂)所引起的本征吸收峰和辐照损伤吸收峰,进行了讨论和指派。2150cm-1吸收峰则被认为是由于氢施主所引起的。 关键词：}     

Coherent excitation of the soft polariton mode in BaTiO3

Coherent excitation of the soft polariton mode in BaTiO₃ is obtained by a two-beam method. The relative power variation on one beam is measured as a function of the polariton frequency (0 < ω_p < 30 cm^?1) for a scattering angle of 0.14° (|k_p| ? 4500 cm^?1) and shows a maximum at ω_p ? 13 cm^?1. By fitting experimental results to the theoretical power variations, the atomic displacive coefficient is determined.     

Pulsed magnetic field study of Fe2+ in some fluosilicates

Pulsed field experiments up to 450 kOe have been performed on FeSiF_6.6H₂O. We interpret the data: (i) in terms of spin hamiltonian constants: D = 12.3± 0.2 cm^-1 (E = 0.54cm^-1 being known from EPR data); (ii) in terms of axial-crystal-field parameters: $\text{δ}\text{λ}\text{=}\text{orbital trigonal splitting/spin-orbit coupling}\text{= 15 ± 2; λ = -100 ± 7cm}{}^{\mathrm{?1}}$. The magnetic axis is found to deviate from the cristallographie c axis by an angle 1° < θ < 2°. The adiabatic cooling obtained during the pulse is discussed.Similar experiments on Fe_0.15Zn_0.85SiF_6.6H₂O and Fe_0.30Zn_0.70SiF_6.6H₂O single crystals are reported; in both cases we measure $\text{D}\text{g}{}_{\mathrm{\parallel }}\text{= 6.0 ± 0.1cm}{}^{-1}$. Using EPR data, we obtain D = 14.3cm^-1, λ ～ ?75cm^-1, δ ～ 195cm^-1; using Mössbauer data, we obtain D = 15.3cm^-1, λ ～ ?88cm^-1, δ ～ 185cm^-1.     

Nonlinear plasma spectroscopy of the hydrogen balmer-α line

The plasma line broadening of H_α fine-structure lines is investigated with Doppler-free saturation and polarization spectroscopy in He-H gas and are discharges at plasma densities of 10⁸ cm^?3 <N?1.4×10¹⁴ cm^?3. With a single-mode laser, the shift and broadening of four resolved H_α fs lines are measured in a low pressure discharge forN<10¹¹ cm^?3. With an intense, broadband multi-mode laser the plasma effects of H_α are investigated up toN=1.4×10¹⁴ cm^?3 in a hollow cathode are. Calculations in the classical phase shift and impact approximations can explain the experimental data and peculiarities of the low-density plasma effects and show that the ions are the dominant perturbers. Ion dynamical effects, perturber mass and temperature dependence, are observed and interpreted. Applications of the nonlinear techniques to other H and D lines, other atoms, and for H and D plasma diagnostics are discussed.     

High-resolution infrared spectrum of CH2D2: The ν3 fundamental band at 7 μm

The infrared spectrum of CH₂D₂ has been recorded in the region of 1345 to 1561 cm^?1 with a resolution of 0.030 to 0.026 cm^?1. Most of the observed lines have been assigned to transitions of the ν₃ band of CH₂D₂. However, 114 lines have been identified as transitions of the ν₂ band of H₂¹⁶O whose band origin has been directly determined to be 1594.7472 ± 0.0030 cm^?1. A few weak lines, probably belonging to the ν₅ fundamental of CH₂D₂, remain unassigned. The band center ν = 1435.1326 ± 0.0030 cm^?1 and a set of upper state constants were obtained for the ν₃ band of CH₂D₂. Although a slight perturbation was noticed in the ν₃ band, all wavenumbers have been fitted with a standard deviation of 3.8 × 10^?3 cm^?1.     

Doppler-limited spectra of the CH stretching fundamentals of formaldehyde

The Doppler-limited spectrum of H₂CO in the 2700 to 3000 cm^?1 region has been recorded using a tunable difference-frequency laser system. This region encompasses the ν₁ and ν₅ fundamental CH stretching bands of formaldehyde as well as a number of strongly interacting combination bands. The tunable laser spectrometer affords complete spectral coverage with a calibration precision better than 10^?3 cm^?1 for the transition frequencies and with absolute absorption intensity measurements better than 2%. The band centers for the ν₁ and ν₅ vibrations are measured to be 2782.4572 ± 0.0010 cm^?1 and 2843.3254 ± 0.0015 cm^?1 respectively, independent of the upper-state rotational constants.     

Additivity and non-additivity of dissociation energies in intermolecular interactions. Theoretical studies on (H2)n,n = 2-8, (CO2)n,n = 2-6 and (HF)n,n = 2-8

CCSD(T) and MP2 results using the aug-cc-pV5Z basis set are reported for chain, cyclic and other structures of the clusters (H₂)_n, n?=?2-8, (CO₂)_n, n?=?2-6 and (HF)_n, n?=?2-8. In chain-like structures of (H₂)_n and (CO₂)_n, with the bonding type of the dimer maintained, the dissociation energy D_e of the dimer doubles for the trimer, triples for the tetramer, and so on. Due to these systems being dominated by short-range forces, interactions are essentially restricted to neighbouring monomers. For other types of (H₂)_n and (CO₂)_n structures, the multipliers relative to the dimerisation energy can be much higher. Dissociation energies for the hexamers in S₆ symmetry of both H₂ (379?cm^?1) and CO₂ (4925?cm^?1) are over ten times the respective dimerisation energies. For the chain-like trimer of HF, however, D_e is in excess of double the dimer value. Mainly due to longer-range dipolar forces, the interactions reach beyond the neighbouring monomers. The interaction energy between HF monomers in chains follows an approximate R^?2 (R being the F–F distance) relationship, The calculated dissociation energies of the HF octamer are 15,985?cm^?1 (factor of 10.4) for the chain, and 21,003?cm^?1 (factor of 13.7) for the C_6h cyclic structure.