The Riemann surface in the target space and vice versa

It is observed that the classical part of the partition function associated with the mappings from a genus-g Reimann surface Σ_g to an “almost complex” target space T_2d is equal to that related to the mappings Σ_d to T_2g. The classical part related to the mappings from a genus-2g Reimann surface Σ_2g described by a “real” period matrix, to a target space T_d is equal to the classical part related to mappings from Σ_2g to T_g. Some physical consequences of these mathematical identities are discusses.     

IR-spectra of (CO2)2 dimers and collision-induced absorption of carbon dioxide in the region of the fermi doublet (ν1, 2ν2)

The positions and intensities of all vibrational transitions in the (ν₁, 2ν₂) Fermi doublet region of (CO₂)₂ dimers are obtained by means of variational method. The collision-induced absorption in compressed carbon dioxide is shown to be mainly due to dimeric absorption. Assignment of ν₁ and 2ν₂ vibrational bands in isolated CO₂ molecule is performed by consideration of the symmetries and intensities of dimeric vibrations.     

Emission spectroscopy of ν10 band of vinyl bromide

By pumping with a pulsed CO₂ laser we have observed many FIR emissions in vinyl bromide that we have assigned to the ν₁₀ band at 942 cm⁻¹. We have been able also to assign many other FIR lines observed in previous works, so that we have derived new spectroscopic constants for the vibrational excited level.     

Spectral intensities in the ν1 band of NH3

Intensities have been measured for individual transitions in the Q and R branches of the ν₁ band of NH₃ using a difference-frequency laser spectrometer. The data yield an integrated band strength of S⁰_v=219.36±1.03 cm^-2/MPa at 297 K, corresponding to a transition moment of μ_v = 8.535(20) × 10^-32 C·m, and a Herman-Wallis correction factor, (1 + _jm)², where _j = 0.0209(20). The intensities of a few lines for K 7 were noticeably perturbed by a perpendicular Coriolis interaction with 2ν₄ (E, L = 2), so were excluded from the fit. A small sample of ν₃ band lines occurring in the ν₁ band scans also yields a rough estimate of the ν₃ band intensity with evident irregular perturbations.     

Cl nuclear quadrupole resonance studies of molecular motions of ClO3 and water diffusion in Ca(ClO3)2·2H2O

A ³⁵Cl nuclear quadrupole resonance (³⁵Cl-NQR) investigation of polycrystalline Ca(ClO₃)₂·2H₂O is described. The ³⁵Cl-NQR frequencies (ν_Q) for two resonance lines (ν_Q1 and ν_Q2), the spin lattice relaxation time (T_1Q) for ν_Q2 only and the line width δν_Q2 were measured in the temperature range 292–345 K, except for the frequency measured up to 455 K. The observed decrease in the resonance frequencies with increasing temperature permitted the determination of the frequencies of librations of the ClO₃⁻ ion about two axes perpendicular to the three-fold axis of the ion mainly responsible for this effect. The temperature dependence of the relaxation time T_1Q proved the occurrence of water diffusion and hindered rotation of ClO₃⁻ ions. The activation energies of these two molecular motions were determined, and their effect on the electric field gradient at the site of a chlorine nucleus was discussed. Temperature measurements of the line width δν_Q2 confirmed the conclusions drawn from the analysis of T_1Q(T).     

Temperature and pressure dependence of NMR frequencies in ferromagnetic Heusler alloys containing cobalt and manganese

The ⁵⁹Co and ⁵⁵Mn NMR frequencies ν in Co₂MnZ (Z = Si, Ge, Sn and Ga) were measured as a function of temperature T and pressure P by the cw method. The ν/ν_4.2 value decreased faster for ⁵⁹Co than for ⁵⁵Mn with increasing T/T_C especially in Co₂MnGa, for which ∂ν/∂P was positive at 0°C in contrast to the results in other alloys.     

Interactions between a tetraanionic porphyrin and the methylviologen dication in methanol studied by fluorescence quenching reaction

Fluorescence decay curves for 5,10,15,20-tetrakis(4-sulfonatophenyl)-21H,23H-porphine tetraanion (TPPS⁴⁻) have been measured in the absence and presence of the methylviologen dication (MV²⁺) with various ionic strengths in methanol. In the presence of MV²⁺ the fluorescence decays can be expressed by a double exponential function, I(t = I₁exp(−t/τ₁) + I₂exp(−t/τ₂). The contribution by the faster decay component to the total fluorescence signal increases with increasing MV²⁺ concentration. The faster decay process is attributed to fluorescence from the excited state of a solvent-separated ion pair (SSIP) formed between TPPS⁴⁻ and MV²⁺, and the slower process is attributed to fluorescence from free TPPS⁴⁻ ions in the solution. Rate constants for the quenching of fluorescence from free TPPS⁴⁻ by MV²⁺ (k_q) and formation constants for the SSIP (K_SSIP) were calculated and both are found to decrease with increasing ionic strength. The decrease in k_q and K_SSIP values can be interpreted in terms of the shielding of electrostatic attraction between the ions.     

Low-energy expansion of meson form factors

We calculate the corrections to various low-energy theorems concerning the behaviour of the pseudoscalar meson form factors near t=0. In particular we discuss (i) the Ademollo-Gatto theorem, (ii) Sirlin's relation between the K_l3 form factor ƒ₊^Kπ(t) and the electromagnetic form factors, (iii) the Callan-Treiman relation, and (iv) the Dashen-Weinstein relation, which connects the slope λ₀ of ƒ₀^Kπ(t) with the ratio F_K/F_π. Furthermore, we point out a remarkable isospin breaking effect which is clearly visible in the experimental rates of the decays K⁺→π⁰e⁺ν, K⁰→π⁻e⁺ν.     

Ab initio calculation of the ground and first excited states of the lithium dimer

Based on a high level ab initio calculation which is carried out with the multireference configuration interaction method under the aug-cc-pVXZ (AVXZ) basis sets, X=T, Q, 5, the accurate potential energy curves (PECs) of the ground state ${\rm{X}}{}^{{\rm{1}}}{\rm{\Sigma }}_{g}^{+}$ and the first excited state ${\rm{A}}{}^{{\rm{1}}}{\rm{\Sigma }}_{u}^{+}$ of Li₂ are constructed. By fitting the ab initio potential energy points with the Murrell–Sorbie potential function, the analytic potential energy functions (APEFs) are obtained. The molecular bond length at the equilibrium (R_e), the potential well depth (D_e), and the spectroscopic constants (B_e, ω_e, α_e, and ω_eχ_e) for the ${\rm{X}}{}^{{\rm{1}}}{\rm{\Sigma }}_{g}^{+}$ state and the ${\rm{A}}{}^{{\rm{1}}}{\rm{\Sigma }}_{u}^{+}$ state are deduced from the APEFs. The vibrational energy levels of the two electronic states are obtained by solving the time-independent Schrödinger equation with the Fourier grid Hamiltonian method. All the spectroscopic constants and the vibrational levels agree well with the experimental results. The Franck–Condon factors (FCFs) corresponding to the transitions from the vibrational level (v′=0) of the ground state to the vibrational levels (v″=0–74) of the first excited state have been calculated. The FCF for the vibronic transition of ${\rm{A}}{}^{{\rm{1}}}{\rm{\Sigma }}_{u}^{+}$(v″=0) ←${\rm{X}}{}^{{\rm{1}}}{\rm{\Sigma }}_{g}^{+}$(v′=0) is the strongest. These PECs and corresponding spectroscopic constants provide reliable theoretical references to both the spectroscopic and the molecular dynamic studies of the Li₂ dimer.     

氨分子在000和201带的选择光离解

本文利用脉冲紫外激光(UV)选择激发氨分子到?¹A″₂电子激发态的两个最低振动能级ν′₂=0和ν′₂=1(ν₂振动),然后检测新生态H原子的飞行谱(TOF),研究了氨分子的光碎片动力学。光谱证实了最近所测的离解能D₀⁰(H-NH₂)=4.645eV;绝大多数生成的NH₂(X²B₁)基处于非振动激发,但是具有围绕a惯性轴的高度转动激发。通过NH₃(?)的ν′₂=1光离解产生的NH₂(X)基具有较高的内部激发,并且显示了在N=K_a转动能级上的反转布居。 关键词：     

Aggregation of phthalocyanine derivatives in liquid solutions and human blood

The aggregation of the copper (II) 4,4′,4′′,4′′′-tetrasulfonated phthalocyanine anion (Cu(tsPc)⁻⁴) has been studied in aqueous solutions, DMSO and in human blood by UV–VIS absorption spectroscopy and resonance Raman spectroscopy (RRS). The vibrational mode ν₄ (1530 cm⁻¹) has been used as a probe in RRS. It has been shown that the dimerization equilibrium constant K is shifted significantly towards monomeric forms when human blood is added to the solution. The life-time of the singlet excited state S_n of (Cu(tsPc)⁻⁴) in aqueous solution has been estimated to be shorter than 500 fs using femtosecond pump-probe absorption spectroscopy.     

Cu1-xHxZr2(PO4)3中Cu2+的EPR谱和局域结构研究

本文采用Cu²⁺斜方对称电子顺磁共振（EPR）参量的高阶微扰公式计算了晶体Cu_1-xH_xZr₂（PO₄）₃中Cu²⁺的EPR参量（g因子和超精细结构常数A因子）．计算结果表明，晶体Cu_1-xH_xZr₂（PO₄）₃中[CuO₆]^10-基团的Cu-O键长分别为R_||≈0.241 nm，R_⊥≈0.215 nm，平面键角τ≈80.1°；由于对称性降低，中心金属离子基态²A_1g（θ）和²A_1g（ε）有一定程度混合，混合系数α≈0.995．所得EPR谱图的理论计算值与实验数据符合得很好．     

非晶锂离子导体B2O3-Li2O-LiCl一Al2O3中VO2+的电子自旋共振

两种非晶锂离子导体B₂O₃-0.7Li₂O-0.7LiCl-xAl₂O₃-0.1V₂O₅(x=0.05和0.15)的电子自旋共振谱研究表明:(i)ESR线型是高斯型,证实V₂O₅添加量适当;(ii)超精细结构来源于VO²⁺络离子,具有四角对称性,属C_4v群。越精细耦合张量的平行分量平均值A_//=0.0175cm^-1,垂直分量A_⊥=0.0063cm^-1。由g_//(g_⊥)求出其基态²B_2g与第一激发态²E_g的能级间距△₁=2.46×10⁴ cm^-1,基态与第二激发态²B_1g的能级间距△₂=3.03×10⁴ cm^-1;(iii)变温实验证实:Al₂O₃组分较少(x=0.05)的非晶ESR强度比x=0.15的非晶高3倍至2倍,而Al₂O₃组分越多则ESR强度随温升下降越小。     

Integrated band intensities in N2O4 in the infrared range

We have measured the integrated band intensities of the ν₉ and ν₁₁ bands of N₂O₄ which are observed around 1757 and 1261 cm^-1, respectively. By varying temperature and pressure, we have obtained: S_band(ν₉) = 9.60(130), 9.10(24), 8.80(66) and S_band(ν₁₁)= 5.93(64), 5.70(21) and 5.33(46) (in 10^-17 cm/molecule) at 293.15 (60), 277.25 (60) and 261.65 (60) K, respectively.     

Intensities of line features in vibration-rotational bands 2–0 to 6–0 of NO XΠr and experimental evaluation of a radial function for electric dipolar moment

We measured the strengths of individual line-like features, representing unresolved Λ doublets, in vibration-rotational bands 2–0 to 6–0 of ¹⁴N¹⁶O within each substate of electronic ground state X²Π_1/2,3/2 in mid and near infrared regions. Analyses of these data to derive values of matrix elements for vibrational transitions enabled production of a radial function for electric dipolar moment, containing seven parameters, that satisfactorily reproduces the intensities of about 700 such features for vibrational states up to ν = 6.     

Continuum absorption of vibrationally excited O2 from 200–320 nm

Cross sections for absorption from excited vibrational levels of the ground X³Σ^-_g state of molecular oxygen to the repulsive 1³Π_u state are given. The potential energy curve for the 1³Π_u state of O₂ is constructed to be consistent with predissociation data for the B³Σ^-u state and with recent ab initio calculations. In the photon wavelength range of 200–320 nm the cross sections are smoothly oscillatory and in no case larger than 1 × 10^-21 cm². In the region of the Schumann-Runge bands the cross sections are of order 0.4 × 10^-21 cm².     

LiAl分子基态、激发态势能曲线和振动能级

利用单双激发多参考组态相互作用方法获得了LiAl分子基态X¹∑⁺及七个激发态a³∏, A¹∏, b³∑⁺, c³∑⁺, B¹∏, C¹∑⁺, d³∏的势能曲线, 通过势能曲线得到各态的平衡核间距R_e, 进而求得绝热激发能和垂直激发能.计算结果表明:c³∑⁺ 电子态是一个不稳定的排斥态, A¹∏态是一个较弱的束缚态, 其余6个电子态均为束缚态; b³∑⁺与 c³∑⁺态之间存在预解离现象; 8个电子态分别解离到两个通道, 即Li(²S)+Al(²P⁰)与Li(²P⁰)+Al(²P⁰). 接着将势能曲线拟合到Murrel-Sorbie解析势能函数形式, 据此获得各态的光谱数据:基态X¹∑⁺的平衡键长为0.2863 nm, 谐振频率为316 cm^-1, 解离能D_e为1.03 eV, 激发态a³∏, A¹∏, b³∑⁺, c³∑⁺, B¹∏, C¹∑⁺, d³∏的垂直激发能依次为0.27, 0.83, 1.18, 1.14, 1.62, 1.81, 2.00 eV; 解离能依次为1.03, 0.82, 0.26, 排斥态, 1.54, 1.10, 0.93 eV, 相应谐振频率 ω_e为339, 237, 394, 排斥态, 429, 192, 178 cm^-1. 通过求解核运动的薛定谔方程找到了J=0时 LiAl分子7个束缚电子态的振动能级和转动惯量. 关键词： LiAl 光谱常数 势能曲线 振动能级     

Optical characterization of amorphous Ga50Se45S5 films

The transmission spectra of thermally evaporated Ga₅₀Se₄₅S₅ films were measured over the wavelength range 300–900 nm. A simple method, suggested by Swanepoel, was used for the determination of the optical constants and thickness of the films. Increasing the thickness of the film beyond 450 nm does not affect the optical constants. The dependence of the absorption coefficient on the photon energy (hν) at the edge of the absorption band is well described by the relation hν=β(hν−E_opt)² with an optical gap equals 2.4 eV. A good fit of the experimental points with Tauc relation indicates that non-direct transition is the most probable mechanism responsible for the photon absorption inside the investigated film.     

Electrostatic stiffness properties of charged bilayers

We calculate the exact stiffness constants χ, , c₀ of mean, Gaussian, and spontaneous curvature for a double layer of surface charges separated by a fixed distance 2d in an electrolyte with finite screening length l₀. This extends earlier studies of the limits of very small and very large d/l_D.     

Infrared reflection-absorption spectroscopy of dipole-forbidden adsorbate vibrations

Formally dipole-forbidden adsorbate vibrational modes have recently been detected using infrared reflection-absorption spectroscopy (IRAS). In an earlier publication we have proposed that the excitation of these modes is indirect, mediated by the metal electrons and closely related to the concept of surface resistivity. Here we extend that theory to lower frequencies; for parallel adsorbate vibrations the theory predicts an anti-absorption resonance with an unique asymmetry which only depends on the ratio ω₀/ω₁ between the adsorbate vibrational frequency ω₀ and ω₁ = v_F/δ where v_F is the Fermi velocity and δ = c/ω_p the skin depth. The theory is in very good agreement with the IRAS measurements of Hirschmugl et al. [Phys. Rev. Lett. 65 (1990) 480] for CO on Cu(100) and in qualitative agreement with the measurements of Lin et al. [Phys. Rev. B 48 (1993) 2791] for CO on Ni(100).