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Hyperfine structure is observed on three transitions of the 5I8?→?5I7 absorption spectrum of the cubic-symmetry centre in CaF2:Ho3+. Hyperfine mixing between the two lowest levels of the 5I8 ground multiplet produces a complex and rich spectrum, which is only partially resolved. Simulated spectra are generated using one parameter to determine electronic crystal-field wavefunctions and one for the crystal-field splitting of the near-degenerate ground state. The simulated spectra correspond well with the measured spectra and demonstrate that the complex structure is well accounted for by dipole-hyperfine mixing between the lowest triplet and doublet states in the 5I8 ground multiplet. 相似文献
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The hot infrared transitions of C2D6 from the υ4(A1u ) to the υ4 + υ6(A2g ) and υ4 + υ8(E g ) vibrational states, observed from 960 to 1180 cm?1, have been rotationally analysed on a high-resolution Fourier transform spectrum (full width at half-maximum about 0·0030 cm?1). The vibration-rotation interactions affecting the upper vibrational states are very similar to those of the corresponding cold system. A strong x,y Coriolis interaction between υ4 + υ6 and υ4 + υ8, with K-level crossing, generates large displacements of the rotational components of both vibrational states, tuning them to additional local resonances in several spectral regions. Thus l resonances with Δl = ±2, Δk = ±1 occur within υ4 + υ8. A x,y Coriolis-type resonance between υ4 + υ8(?l,K ? 1) and υ3 + 2υ4(K) occurs at K = 11,12,13, and a further coupling of υ4 + υ8(+l,K + 1) and υ3 + 2υ4(K + 3) is most effective at K = 11 and 12. These resonances induce torsional splittings on the perturbed levels of υ4 + υ8 and allow us to determine the torsional splittings in the υ3 + 2υ4 state. The vibration-rotation constants of υ4 + υ6, υ4 + υ8 and υ3 + 2υ4, several interaction parameters and the torsional splitting of υ3 + 2υ4 have been determined by least-squares fit of 1391 observed transition wavenumbers, with an overall standard deviation σ = 0·75 × 10?3 cm?1. The vibrational wavenumbers found for the four torsional components of (υ3 + 2υ4)? υ4 are υ(E3d) = 1040·961 82(809)cm?1, υ(A3d) = 1041·218 27(865)cm?1, υ(E3s) = 1041·225 23(662)cm?1 and υ(A1s) = 1041·407 77(633)cm?1. These are anomalous for both the order of the torsional components and the magnitudes of their separations. We believe that this is mainly due to the interactions of υ3 + 2υ4 with the torsional manifolds with υ3 = 0 and υ3 = 2, through the vibration-torsion Hamiltonian term (?V 6/?q 3)q 3cos (6γ)]/2. The further observation of a few doublets of υ8 and υ3 + υ4 at resonance provides information on the torsional splitting of the latter state. 相似文献
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Mazzera M Capelletti R Baraldi A Buffagni E Magnani N Bettinelli M 《J Phys Condens Matter》2012,24(20):205501
High resolution spectroscopy (the finest being 0.01 cm(-1)) was applied in the 75-25,000 cm(-1) and 9-300 K ranges to a 1 mol% holmium doped Y PO(4) single crystal with two purposes: (1) to study the hyperfine splitting of Ho(3+) energy levels of interest for possible quantum manipulation media and (2) to analyze the electron-phonon interaction. The hyperfine structure was clearly revealed for a high number of lines in a wide wavenumber range (up to ~21,500 cm(-1)) and for a large number of multiplets. Several hyperfine patterns were monitored, differing in the number of components (a maximum of 16 could be easily distinguished in a single beautiful pattern), in their separation, and in their relative statistical weight. These features were all understood in terms of a crystal-field model, whose results are in good agreement with experiments and account for the involved level symmetry, the type of transitions (electric and magnetic dipole allowed), and the contribution of a second-order (pseudoquadrupolar) hyperfine coupling between close levels. The electron-phonon interaction, investigated through the thermally induced line shift, was critically discussed in the framework of single phonon coupling and of two phonon Raman scattering models. 相似文献
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《Solid State Communications》1986,59(7):461-463
Variations in the decay times of the characteristic green emissions at 522.7, 551.3, 549.6, 547.6, 542.2, 540.2, 535.9 and 533.5 nm from CaF2:Ho3+ with concentration are studied at RT and LNT. A pulsed N2 laser beam of power density 1.5 MW cm-2 is used for the excitation. Temperature dependent concentration quenching of the decay times are observed for all the emission bands. But an increase in the decay time due to the reabsorption process is also observed for a few of the above bands. 相似文献
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D. HURTMANS A. RIZOPOULOS M. HERMAN L. M. S. HASSAN A. PERRIN 《Molecular physics》2013,111(5):455-461
A Fourier transform interferometer was used to record the slit-jet cooled absorption spectrum of 12C2H4 between 700 and 2400 cm?1I, at a spectral resolution of 0.005 cm?1. Three bands, v12 at 1442.442 70(1)cm?1, v7 + v8 at 1888.978 23(3)cm?1 and v6 + v10 at 2047.775832(2)cm?1, were rotationally analysed. In the case of 7181, a known Coriolis perturbation mechanism involving the nearby 4181 (1958.264cm?1) and 81101 (1766.391 cm?1) states was accounted for in the analysis. The latter fitting procedure included 12 levels from the 4181 state which are observed because lines from v4 + v8 borrow intensity from v7 + v8. Compared to the literature, significantly improved vibration-rotation constants were obtained for all upper states reported in the present study. 相似文献
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J. Hietanen 《Molecular physics》2013,111(5):1029-1038
In the infrared spectrum of C2H2 around the fundamental v 5, the hot bands starting from the levels 2v 5, 2v 4 and v 4 + v 5 have been investigated. From the analysis of about 20 different bands, 40 molecular constants describing the bending modes v 4 and v 5 have been derived. 相似文献
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The hyperfine structure of 127I2 and 129I2 rovibronic absorption lines was investigated using either laser induced fluorescence of a collimated molecular beam or saturated absorption in a cell. From the measurements a value for the quadrupole moment ratio is deduced, in good agreement with the result obtained from pure quadrupole spectra in the rf range. 相似文献
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H. Wang C. Tu Z. You F. Yang Y. Wei Y. Wang J. Li Z. Zhu G. Jia X. Lu 《Applied physics. B, Lasers and optics》2007,88(1):57-60
NaGd(WO4)2:Yb3+, Ho3+ single crystals have been grown by the Czochralski technique along the (0 0 1) orientation. Conversion of the infrared (IR)
radiation at 980 nm into the visible emission in NaGd(WO4)2 crystals containing several different concentrations of Yb3+ and Ho3+ has been investigated. The NaGd(WO4)2: 8 at. % Yb3+, 4 at. % Ho3+ system exhibits intense red upconverted emission originating from the 5F5
level. The upconversion mechanism in a Ho3+-Yb3+ system under near infrared excitation is discussed. It is concluded that the green emission is excited by energy transfers
from Yb3+ to Ho3+, whereas excited state absorption is involved in the excitation of red emission. The emission cross-section of the 5F5→5I8 transition at about 660 nm was estimated by using the Füchtbauer–Ladengurg formula.
PACS 78.55.Hx; 78.20.-e 相似文献
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摘要:报道了对Tm,Ho双掺YVO4晶体光谱性能的测量结果,包括用UV-365型分光光度计测出单掺Tm:YVO4及Ho:YVO4吸收谱以及双掺Tm:Ho:YVO4的吸收谱;用Ar离子激光器488nm,LD激光器激发测量样品荧光光谱;用J-O理论进行光谱参数计算及对能级结构进行分析;研究了在λ=805nm的激光二极管激发下Tm对Ho的敏化发光过程。发现与YAG,YLF为基质的Tm,Ho双掺材料相比,该材料中的Tm3+离子具有大而均匀的吸收宽度(~26nm),大的峰位吸收截面和积分吸收截面(~1.4×10-20cm2和274.5×10-20
cm),能量转换效率高(可达87%),且泵浦阈值低(~15mW)。表明了YVO4晶体中Tm能有效地敏化Ho,并产生2μm的发射。文中对发射强度与泵浦功率及Tm,Ho之间掺杂浓度的关系进行了初步的分析与讨论。光谱的观察结果表明:在实现LD泵浦,全固体化,小型,高效的,2μm激光振荡的探索中,Tm:Ho:YVO4晶体将是一种很有实际应用潜力的材料。 相似文献