Intensity distribution in the bands of the D1 → X1∑+ system of PbO

Relative integrated intensities of the D1 → X¹∑⁺ system of PbO have been measured by heterochromatic photography photometry. The Morse potential has been employed to compute the Franck-Condon factors and r-centroids. The variation of electronic transition moment R_e with internuclear separation r is found to be R_e(r) = const × (0.54 r − 1) in the range 1.957 ⩽ r, Å ⩽ 2.051. Relative band strengths are derived. The effective vibrational temperature of the source was 6199 K.     

Laser spectroscopy of YBr: rotational analysis of the B1Π—X1Σ system

The (ν,0) bands, for ν = 0–5, of the B¹Π-X¹Σ transition of YBr between 806.2–891.2 nm have been studied using the technique of laser vaporization/reaction with supersonic cooling and laser-induced fluorescence spectroscopy. Spectra of both the Y⁷⁹Br and Y⁸¹ Br isotopic molecules were observed and analysed. A least-squares fit of all the measured line positions yielded vibrational and rotational constants for the B¹Π state. The equilibrium bond length of the B¹Π state is determined to be 2.622 5(2) Å.     

Rovibrational transition properties of the X1Σ+ and A1Π states of carbon monosulfide

Carbon monosulfide was detected in outer space by rovibrational spectroscopy of the X ¹Σ⁺ state and A ¹Π – X ¹Σ⁺ system. This work calculated the potential energy curves and dipole moment functions of the X ¹Σ⁺ ₀₊ and A ¹Π₁ states, and computed the transition dipole moments between the two states employing the CASSCF method, followed by the valence icMRCI approach. Core-valence correlation and scalar relativistic corrections were included. The extrapolation of potential energies to the complete basis set limit was performed. The spin-orbit coupling effect was included. The Einstein A coefficients, band origins, and oscillator strengths were calculated for the rovibrational transitions when J?≤?150. The rovibrational transitions of the X ¹Σ⁺ ₀₊ and A ¹Π₁ states became very weak when Δυ?≥?6. The Einstein A coefficients of vibronic emissions of the A ¹Π₁ – X ¹Σ⁺ ₀₊ system were large, indicating that the emissions were able to be measured easily through spectroscopy. Several rovibrational transitions of the A ¹Π₁ – X ¹Σ⁺ ₀₊ system were analysed in detail. The distribution of radiative lifetime varying as rotational quantum number was calculated. The results obtained in this work agree well with the available experimental values.     

Calculation of the Mass of X（3872） by the Mandelstam Generalization of the Gell-Mann-Low Method

On the basis of assuming that the narrow state X（3872） is a molecule state consisting of D0 and D＊0, we apply the Mandelstam generalization of the Ge11-Mann-Low method to calculate the matrix element of quark current between the heavy meson states described by Bether-Salpeter wave function. In calculation of the matrix element of quark current the operator product expansion is used in order to include the nonperturbative contribution of the vacuum condensates. In this scheme we calculate the mass of X（3872）. We believe that this scheme is closer to QCD than the previous work.     

Ab initio CI study of the vibrational structure of the 1 1Σ− (1 1 A″)←X and 1 1Δ (2 1 A′, 2 1 A″)←X electronic transitions in HCN and DCN

The results of an ab initio CI study of the vibrational/vibronic structure of the 1 ¹Σ^? (1 ¹ A″)←X and 1 ¹Δ (2 ¹ A′, 2 ¹ A″)←X electronic transitions in HCN and DCN are presented. Calculated band positions and intensity distributions within the band progressions are compared with corresponding experimental data. While the theoretical results for the 1A″←X transition reproduce well the structure of the observed A-X spectrum, they place doubt on the Bickel-Innes interpretation of the B-X band system in terms of transitions to the same excited electronic state but accompanied by excitation of a single quantum of the C?H stretching vibrational mode.     

Determination of the Spin-parity of the Boson Resonance X for the Process J/ψ→V1+X,X→γ+V2

The angular distribution for the process J/ψ→V₁+X,X→γ+V₂,V₂→2P or 3P(where V₁ and V₂ stand for the vector mesons,P is the pseudoscalar meson) are presented.They can be used to distinguish the spin of the boson resonance X and determine the space parity in some special cases.     

π-Electron Densities in Molecules ΦCHX1X2 and Correlation with the Intensity of the 00 Band of the Secondary Transition

In molecules such as ΦX₁X₂X₃the intensity of the secondary transition of the benzene chromophore, strongly depends on long range interactions involving a σ·π coupling between orbitals belonging to the C_α-X bonds, and the πΦ system. Such a coupling distorts the symmetry of the π_Φ system(1–5). The secondary transition (towards 260 nm) which is forbidden when the symmetry is D_6h - as in the benzene molecule itself where only the low intensity progression A isobserved - becomes all the more allowed as the substituent is able to distort the πΦ cloud towards a C_2V symmetry. A new progression called B is observed. Its intensity is usually evaluated by the measure of its 00 band. The distorsion of symmetry arises because of the π donating or π withdrawing electronic effects of the substituent(1–7). These phenomena have been explained on the ground of a V shaped function(l) : ε₀₀ = f(σ), where σ is a parameter linked to the electronic effects of the substituents. When the whole substituent is a π donating one, its π donating effect is lowered by an increase of the electron attracting power of the groups X : the perturbation of the D_6h symmetry is lessened and ε₀₀ decreases. On the contrary, when the whole substituent is a π withdrawing one, an increase of the withdrawing power of the groups X increases the withdrawing power of the whole substituent, the distorsion of the D6h symmetry increases and ε₀₀ increases too. The minimum of the V shaped curve correspond to the species for which the π donating tendency of the aliphatic part of the substituent is quenched by the electron withdrawing tendency of the groups X. The D_6h symmetry of the πΦ cloud is restored. The transition is forbidden and the system A only is observed.     

On the mass of the ss^- member of the 1^3D1 meson nonet

In the framework of Regge phenomenology and meson meson mixing, this paper estimates the mass of isoscalar state （ss^-） of the 1^3D1 meson nonet, and the results given by two different approaches are 1735.51 ± 59MeV and 1730.29 ±46.SMeV.     

Transition probabilities of the X1Σ+, A1Π, B1Δ, C1Σ+, and D1Π states of the AlO+ cation

ABSTRACT

This study computes the potential energy curves of the X¹Σ⁺, A¹Π, B¹Δ, C¹Σ⁺, and D¹Π states of AlO⁺ cation and the transition dipole moments between them. The orders of the rotationless radiative lifetimes are 10–100?μs for the A¹Π state, 1–1000?ms for the B¹Δ state, 10?ns for the first well and 100?ns for the second well of the C¹Σ⁺ state, and 1?μs for the D¹Π state. Emissions of the B¹Δ–A¹Π and D¹Π–C¹Σ⁺ systems are so weak that they are hardly measured via spectroscopy, the emissions of the C¹Σ⁺–X¹Σ⁺, C¹Σ⁺–A¹Π, and D¹Π–X¹Σ⁺ systems are so strong that they can be detected readily, and emissions of the A¹Π–X¹Σ⁺ and D¹Π–A¹Π systems can be observed through spectroscopy only by a significant effort. There is a strong great similarity between spontaneous emissions of the A¹Π–X¹Σ⁺ system of the AlO⁺ cation and the A²Π–X²Σ⁺ system of the AlO radical. The emissions of the A²Π–X²Σ⁺ system of the AlO radical have been measured in outer space Therefore, it is highly possible that the emissions of the A¹Π–X¹Σ⁺ system of the AlO⁺ cation can be detected in the astrophysical media.     

New analysis of the Douglas-Herzberg system (A1Π- X1Σ+) in the CH+ ion radical

Three bands of the A¹Π- X¹Σ⁺ system in the ¹²CH⁺ ion radical have been rephotographed under high resolution as an emission spectra using a Geissler-type discharge tube. The conventional technique of spectroscopy has been implemented. Using the Th lines as a standards, as well as an interferometric comparator equipped with a photoelectric scanning device, the 0-0 , 0-1 and 2-1 bands have been reanalyzed. By means of much longer bands (J_max = 17 in the Q(J) branch of the 0-0 band; J_max = 16 in the R(J) branch of the 0-1 band; J_max = 14 in the P(J) and Q(J) branches of the 2-1 band), than have been observed so far, as well as the merged calculations, using another five bands given by Carrington et al. [A. Carrington, D.A. Ramsay, Phys. Scripta 25, 272 (1982)] additionally, more accurate molecular constants for the X¹Σ⁺ state, the improved reduced band system origin T_e = 24118.726 (14) cm^-1 as well as for the first time the equilibrium molecular constants with their one standard deviation for the A¹Π state in the CH⁺ molecule have been computed: ω_e'=1864.402(22), ω_ex_e'=115.832(14), ω_ey_e'= 2.6301(24), B_e'=11.88677(72), α_e'= 0.9163(18), γ_e'= -2.29(12)×10^-2, ε_e'= 4.95(20)×10^-3, D_e'=1.92960(31)×10^-3, β_e'= 1.0733(50)×10^-4, δ_e'= -1.312(16)×10^-5, , α_qe'= -3.14(16)×10^-3, and q_De'= -2.20(14)×10^-5 cm^-1. Only in our research the addition to the zero-point energy Y'₀₀=-1.9430 cm^-1 and cm^-1 have been calculated. The equilibrium bond lengths of r'_e=1.235053(37) ? and ? for the A¹Π and X¹Σ⁺ states, respectively have been computed. Full quantum-mechanics characteristic of the A-X bands system in the ¹²CH⁺ molecule, i.e. RKR turning points, the Franck-Condon factors and r-centroids have been obtained. Dissociation energies D_e^{X1 Σ+}=(38470± 3503) cm^-1 and D_e^{A1 Π}= (14415 ±3509) cm^-1 for the molecule under consideration have been estimated.     

Determination of the Elemental Composition of Chalcogenide Powders by the X‐Ray Fluorescence Method

A procedure of xray spectral fluorescence analysis of the elemental composition of As _x S_100–x chalcogenide powder samples is developed and its metrological characteristics are established. In determining the content of the components in an As₅₀S₅₀ sample, the relative standard deviation was 0.0030 for As and 0.0035 for S. The results of the xray spectral fluorescence analysis are in good agreement with the data of a gravimetric method.     

Spectroscopic determination of Fisher information on vibrational states of diatomic molecules using the example of the X 1Σ g + state of a Li2 molecule

An expression governing Fisher information of vibrational states of a diatomic molecule is obtained in the first-order Wentzel-Kramers-Brillouin (WKB) approximation, and a quantitative criterion of its applicability is proposed. The expression is determined only by the dependence of energy of vibrational levels on quantum number v and the reduced mass of the molecule; it is not related to any additional model assumptions and does not require knowledge of vibrational wavefunction. It is established that the dependence of Fisher information on v attains maximum at certain value v ₀. The efficiency of the obtained expression is demonstrated by calculating the Fisher information of vibrational levels v = 0–40 of the X ¹Σ _g ⁺ state of the ⁷Li₂ molecule. It is established that v ₀ = 23 for this electronic state. Calculation of the Fisher information of levels v = 0–38 of this state with the help of the obtained relation is in excellent (within mean-square deviation σ? = 0.01%) agreement with the results of calculation based on numerical solution of the Schrödinger equation by using the earlier-published semi-empirical potential curve of this state. At the same time, the expressions available in the literature based on the Wilson-Sommerfeld quantization rule describe the Fisher information of these levels only qualitatively (σ? = 18%). It is established that the reason for deviation for levels v = 39 (σ = 0.3%) and v = 40 (σ = 1.9%) is not related to using the WKB approximation but is due to the numerical differentiation procedure of strongly nonlinear (in the vicinity of the upper bound of v) dependence of the energy of vibrational terms on v appearing in the obtained expression.     

Relaxation of the analyzing power of the (p, τX) and (p, αX) reactions in the continuum

The observed continuous decrease of the analyzing power for the reactions ($\text{p}$, τX) and ($\text{p}$, αX) on ⁹⁰Zr and ²⁰⁹Bi at E_p = 72 MeV as a function of the excitation energy of the final nucleus is described by a phenomenological relaxation process.     

A Reanalysis of theA1Π–X1Σ+Transition of AlBr

TheA¹Π–X¹Σ⁺transition of aluminum monobromide (AlBr) near 2800 Å was recorded using a Bruker IFS 120 HR Fourier transform spectrometer at nominal resolutions of 4 and 0.03 cm⁻¹. All bands showP,Q, andRbranches and all are degraded to longer wavelengths. The 0–0 band is the most intense and the Δv= 0 sequence dominates the observed spectrum. Each band appears doubled due to the natural isotopic abundances of⁷⁹Br (50.69%) and⁸¹Br (49.31%). Band origin shifts due to isotopic substitution of bromine were examined to confirm the assignments of isotopic species. The rotational structure of the 0–1, 1–2, 0–0, 1–1, and 2–2 bands was assigned and fitted. These data were merged with previously reported photographic data for the 1–0, 2–1, 3–2, 2–0, and 3–1 bands and also infrared and microwave measurements to provide an improved set of constants for both electronic states. The rotational constants for each vibrational level in theX¹Σ⁺state vary smoothly with increasing vibrational quantum number and thus an expansion of the constants in terms of equilibrium values is recommended. An expansion of theA¹Π rotational constants in terms of equilibrium values is not recommended as the distortion constants do not change smoothly with increasing vibrational quantum number. Therefore, the rotational constants for theA¹Π state were determined for each individual vibrational level. This approach leads to vastly improved vibrational constants for theA¹Π state by reducing correlations between rotational and vibrational constants. This problem is serious for theA¹Π state owing to severe departures from harmonic behavior in thev= 2 andv= 3 levels.     

Phase diagram of the system of solid solutions Pb1−X(Li½La½)X(Zr1-YTiY)O3 in the vicinity of the FE-AFE phase stability boundary. II. phase transitions and induced states

Results of the study of phase transitions in the system of solid solutions Pb_1-X(Li_½La_½)_X(Zr_1-YTi_Y)O₃ (PLLZT) at x = 0, 1 under the effect of an electric field are presented. It is shown that there are three regions of Ti-concentration on the “;composition-temperature”; phase diagram. The region of Ti-content from ～ 12 to ～ 19% is the most interesting. In this region the succession of phase transitions depends on the prehistory of the specimens: in the absence of an external electric field only the AFE-PE transition takes place, but after the action of the field, the succession of phase transitions FE-AFE-PE arises. Full “;temperature-field”; phase diagrams are constructed.     

Phenomenology of spin observables in the reactions of meson production with the 1 S 0 Diproton pN → {pp} s X

Formalism for spin observables for production of pseudoscalar, scalar, and vectormesons in pN collision with formation of the ¹ S ₀ diproton {pp} _s in the final state is considered in model-independent way assuming parity and angular momentum conservation. Production of the pseudoscalar mesons (J ^π = 0^?) is described by two spin amplitudes and both of them can be completely determined by measurement of unpolarized cross section dσ ₀, vector analyzing power A _y , and spin-correlation coefficients C _x,x = ?C _z,z > and C _x,z . Similar result is obtained for production of scalar mesons (J ^π = 0⁺). It is shown that measurement of the tensor polarization t ₂₀ of the vector meson V (J ^π = 1^?) in the reaction pN → {pp} _s V in collinear kinematics gives the same information as measurement of the spin-correlation coefficients C _z,z or C _y,y .     

Rotational Analysis of the 1–4 Band of the B 2Σ+–X 2Σ+ System of 14C16O+

ABSTRACT

High-resolution emission spectrum of the 1–4 band of the B ²Σ⁺–X ²Σ⁺ transition of ¹⁴C¹⁶O⁺ was observed for the first time by conventional emission spectroscopy. The band spectrum was excited in a water-cooled Geissler lamp filled with commercial gaseous carbon monoxide enriched in about 80% of the radiocarbon ¹⁴C. A rotational analysis has been carried out and obtained molecular constants have been merged with previously published data for the B ²Σ⁺–A ²Π_i and A ²Π_i–X ²Σ⁺ transitions. The principal equilibrium constants for the ground X ²Σ⁺ state obtained from this work are ω_e = 2121.7726(98), ω_e x _e = 13.9055(27), B _e = 1.815290(30), α_e = 1.6594(33) × 10^?2, and γ_e = ? 0.377(73) × 10^?4 cm^?1. Also, presently known experimental equilibrium molecular constants of the X ²Σ⁺ states of the CO⁺ isotopic molecules are summarized and isotopic dependence of the B _e and ω _e constants is discussed.