Electronic-excitation transfer collisions in flames—V. Cross sections for quenching and doublet-mixing of K(42P)-doublet by N2, O2, H2 and H2O

Weighted average cross sections for quenching of the K(4²P)-doublet by N₂, H₂, O₂ and H₂O, measured in flames, show no significant temperature dependence in the range from 1500 to 2500K. Doublet mixing cross sections for K(4²P$\text{3}\text{2}$?4²P$\text{1}\text{2}$) transitions were measured at 1720K for N₂, O₂, H₂O. The ratios of both mixing cross sections were measured independently and were found to agree with the detailed balance condition within 2 per cent. It is shown that an ionic intermediate-state model cannot explain the large magnitude of N_2? mixing cross sections.     

The reactions 18O(p,p)18O and 18O(p,p')18O1(1.98 MeV) for Ep = 3.8–6.1 MeV

Angular distributions of cross sections and analyzing powers have been measured for ¹⁸O(p, p)¹⁸O and ¹⁸O(p, p₁)¹⁸O¹ (1.98 MeV) in 25 keV intervals for proton energies between 3.8 and 6.1 MeV. A phase-shift analysis of the elastic scattering data was carried out, yielding resonance parameters for 16 levels in ¹⁹F in the excitation energy region 11.6–13.8 MeV. The results generally are in good agreement with previous work. On the basis of spin, parity, excitation energy and a comparison of reduced proton widths with reduced neutron widths of levels in ¹⁹O, an assignment of $\text{T =}\text{3}\text{2}$ could be made to at least five of the levels, including the analog of the broad $\text{3}\text{2}{}^{\mathrm{+}}$ level in ¹⁹O at 5.45 MeV. A Legendre-polynomial analysis of the inelastic scattering data suggests that the cross section for proton energies between 5.0 and 5.5 MeV is dominated by the broad $\text{3}\text{2}$⁺ resonance at E_p = 5.15 MeV.     

Etude de 17N par la reaction 18O(t, αγ)17N

The first six excited states of ¹⁷N have been studied by using the ¹⁸Ot, αγ)¹⁷N reaction at a bombarding energy of E_t = 3.5 MeV. Alpha-gamma angular correlation measurements (method II) were used to determine spins, mixing ratios and branching ratios. The 1.37, 1.85, 1.91, 2.53, 3.13 and 3.20 MeV levels have been assigned the spins $\text{3}\text{2}$, $\text{1}\text{2}$, $\text{5}\text{2}$^?, $\text{5}\text{2}$⁺, $\text{7}\text{2}$ and $\text{3}\text{2}$ respectively. Excitation energies are also given. Most of the results are in good agreement with previous data or suggested values. Mixing ratios have been obtained for the first time. The level scheme of ¹⁷N is compared with some $\text{T =}\text{3}\text{2}$ analogue states in ¹⁷O and ¹⁷F and with results of recent shell-model calculations.     

Electronic transition moments between excited singlet states of the H2 molecule

The twelve transition moments which connect each of the three ¹Σ_g⁺ states EF, GK, and $\text{H}\text{H}$ with the three ¹Σ_u⁺ states B,B′, $\text{B″}\text{B}$ and with the state C¹Π_u were computed in the range of internuclear distances 1.25 ≤ R ≤ 15 a.u. using accurate electronic wavefunctions. The relative phases of the wavefunctions, which determine the signs of the transition moments, were consistently defined at all R values. The strong R dependences of the transition moments reflect the R-dependent changes in electronic character of the states involved in these transitions. At large R values the ¹Σ_g⁺-¹Σ_u⁺ transition moments are dominated by the two-electron charge resonance in the ionic configuration H⁺ + H^? whose transition moment is $\text{M(R) ? R}$.     

Spectroscopic analysis of the d1Σ+→a1Σ+ and d1Σ+→b1Π green band systems of XeO

A comprehensive high resolution spectroscopic analysis has been made on the XeO green bands photographed in emission from an RF discharge source. Rotation-vibration constants derived from the analysis of the spectrum of the isotopically enriched species ¹²⁹Xe¹⁶O and ¹²⁹Xe¹⁸O were used to give RKR potential curves for the d¹Σ⁺ and b¹Π states. The bond distances and dissociation energies of the d¹Σ⁺ and b¹Π states were respectively found to be $\text{r}{}_{\mathrm{e}}\text{= 2.852 ± 0.002}\text{A}\text{?}$, D_e = 693 ± 10 cm^?1 and $\text{r}{}_{\mathrm{e}}\text{= 2.548 ± 0.002}\text{A}\text{?}$, D_e = 461 ± 10 cm^?1. For the a¹Σ⁺ state it was not possible to establish a unique vibrational numbering or to construct an RKR potential curve, since observed bands of the d¹Σ⁺→a¹Σ⁺ system involve only high vibrational levels of the a¹Σ⁺ state, which are severely predissociated. The observations are consistent with a fairly deep well, in agreement with the latest ab initio calculations which give a well depth of 0.7 eV.     

A study of the rotational side-bands in 162Dy

Rotational side-bands in ¹⁶²Dy have been studied using the ¹⁶⁰Gd(α, 2nγ)¹⁶²Dy reaction. Seven side-bands are observed, with K^π = 2⁺, 2^?, (0)^?, 0⁺, 5^?, 4⁺ and (6^?). Four of these bands have collective structure at low spin: the K^π = 2⁺γ-vibrational band, the K^π = 0⁺β-vibrational band, and the K^π = 2^? and (0)^? octupole vibrational bands. Of the remaining bands, the 4⁺ band is deformation coupled while the 5^? and (6^?) bands are rotation-aligned. Several bandcrossings are observed in this nucleus. The β and γ-bands are crossed at $\text{I = 6}\text{h}\text{?}\text{and}\text{12}\text{h}\text{?}$, respectively, by a highly aligned ($\text{i}{}_{\mathrm{<mtext>13</mtext><mtext>2</mtext>}}$)² S-band; extrapolation of this S-band to higher spin suggests that it crosses the g.s.b. between $\text{I = 18}\text{h}\text{?}\text{and}\text{20}\text{h}\text{?}$. The 2^? octupole band is crossed by the 5^? band at $\text{I = 9}\text{h}\text{?}$ and again by the (6^?) band at $\text{I = 12}\text{h}\text{?}$. The latter bandcrossings are discussed in terms of two-quasiparticle plus rotor calculations.     

Spin-parity assignments to high-spin states of 41K and 41Ca

Yrast states of ⁴¹K and ⁴¹Ca have been investigated with the ²⁶Mg(¹⁸O, p2nγ)⁴¹K and ²⁶Mg(¹⁸O, 3nγ)⁴¹Ca reactions at a beam energy of 34 MeV. Gamma-gamma coincidence, γ-ray angular distribution and linear polarization measurements were performed with a Ge(Li)-NaI(Tl) Compton suppression spectrometer and a three-crystal Ge(Li) Compton polarimeter. Unambiguous spin-parity assignments of $\text{J}{}^{\mathrm{\pi }}\text{=}\text{7}\text{2}{}^{\mathrm{+}}$, $\text{11}\text{2}{}^{\mathrm{+}}$, $\text{11}\text{2}{}^{\mathrm{?}}$, $\text{13}\text{2}{}^{\mathrm{+}}$, $\text{15}\text{2}{}^{\mathrm{?}}$ and $\text{19}\text{2}{}^{\mathrm{?}}$ to the ⁴¹K levels at E_x = 1.68, 2.53, 2.76, 2.77, 4.27 and 4.98 MeV and of $\text{9}\text{2}{}^{\mathrm{+}}\text{,}\text{11}\text{2}{}^{\mathrm{+}}\text{and}\text{15}\text{2}{}^{\mathrm{+}}$to the ⁴¹Ca levels at E_x = 3.20, 3.37 and 3.83 MeV, respectively, have been obtained. Excitation energies, branching ratios, multipole mixing ratios and transition strengths are reported. The main features of the ⁴¹K and ⁴¹Ca level and decay schemes are reproduced in a 2p-1h and 3p-2h shell-model calculation.     

Evidence for assignment of 14.0 MeV state in 11B from 10B(n,n)10B

The differential cross section and polarization for neutrons scattered from ¹⁰B have been measured at E_n = 2.63 MeV (E_x = 13.85 MeV). The results of this experiment and other available neutron scattering data in the range 1 < E_n < 4 MeV are interpreted through a single-level R-matrix calculation over the region 12 < E_x < 15 MeV. Based on this analysis the most probable J^π assignment for the 14.0 MeV level in ¹¹B is $\text{11}\text{2}{}^{\mathrm{+}}$. The anomaly near E_x = 13.1 MeV can only be explained in terms of two overlapping levels having assignments of ($\text{5}\text{2}$, $\text{7}\text{2}$)^? and ($\text{3}\text{2}$, $\text{5}\text{2}$, $\text{7}\text{2}$)⁺.     

Exotic decays of the muon and heavy leptons in gauge theories

We have studied the decay ?₁ → ?₂ + γ for arbitrary like charged spin $\text{1}\text{2}$ leptons in a manner which is applicable to a large class of models. Our computations assume that this process is induced by one loop diagrams. When the leading effect is cancelled by a leptonic G.I.M. mechanism, we find an extremely large enhancement of O(M_W⁴/M_L⁴) in Λ(μ^?→e^?+e⁺e^?)/Λ(μ^?→e^?+γ) if the intermediate lepton is charged.     

Collisional quenching of HgBr(B2∑+12)

Rate coefficients for the quenching of HgBr(B²∑⁺_{$\text{1}\text{2}$}) by HgBr₂, H₂, CO₂, CO, O₂, N₂, Xe, and Br₂ are reported. HgBr(B²∑⁺_{$\text{1}\text{2}$}) is formed by the photolysis of HgBr₂ with the output from an ArF laser. The rate coefficients are determined by monitoring the time resolved B²∑⁺_{$\text{1}\text{2}$} → X²∑⁺_{$\text{1}\text{2}$} emission as quenching species are added. Radiative lifetimes at particular emission frequencies are also reported, and quenching mechanisms are discussed.     

The photoelectron angular distributions of HBr and HI AT hν = 21.2 eV

Photoelectron angular distributions for the ²Π_{$\text{3}\text{2}$, $\text{1}\text{2}$}(pπ)^?1 and ²Σ_{$\text{1}\text{2}$}⁺(pσ)^?1 ionic states of HBr and HI have been measured at a photon energy of 21.2 eV. The asymmetry parameters for the highly localized pπ orbitals closely follow those of the “lone-pair” orbitals of the related CH₃X molecules and the outer np atomic orbitals of the corresponding united atoms. Furthermore, the asymmetry parameters for the ²Π_{$\text{3}\text{2}$} and ²Π_{$\text{1}\text{2}$} states were found to be equal within experimental uncertainty, despite the large spin—orbit splittings of these heavy molecules. The asymmetry parameters for the ²Σ⁺(pσ)^?1 ionic states are significantly smaller than for the ²Π(pπ)^?1 states, in contrast to recent predictions based on angular momentum transfer theory.     

Structure of 0+ states in 18O

Analysis of spectroscopic factors obtained in single-nucleon transfer reactions leading to and from ¹⁸O yields two different sets of wave functions for the first three O⁺ states. One set of wave functions is in agreement with ¹⁶O(t, p)¹⁸O data for the three states-the other set is not. The wave functions that agree with the experimental data have the majority of the $\text{(s}\text{1}\text{2}\text{)}{}^2$ strength in the third O⁺ state.     

Scaling of the “superstable” fraction of the 2D period-doubling interval

The scaling properties of a “superstable” parameter interval, $\text{C}$, where the eigenvalues about a period-2n orbit are complex, are derived for 2D period-doubling maps. The ratio of $\text{C}$ to the whole parameter interval, between the nth and the (n+1)st bifurcation, is shown to be a universal function of the effective jacobian, B_e, only (B_e≡B²ⁿ, B is thejacobian of th e map). Unlike the whole period-2ⁿ interval, $\text{C}$ has a convergence rate that behaves as $\text{4.6692016×B}{}^{\mathrm{<mtext>-1</mtext><mtext>4</mtext>}}{}_{\mathrm{e}}$ as B_e↓), wh ile its complement has a convergence rate 8.7210972/4 as B_e↑1.     

Microwave optical double resonance and continuous wave dye laser excitation spectroscopy of NO2: Rotational assignment of the K = 0−4 subbands of the 593 nm band

A rotational assignment of approximately 80 lines with K_a′ = 0, 1, 2, 3, and 4 has been made of the 593 nm ${}^2\text{A}{}_1\text{→}{}^2\text{B}{}_2$ band of NO₂ using cw dye laser excitation and microwave optical double-resonance spectroscopy. Rotational constants for the ²B₂ state were obtained as A = 8.52 cm^?1, B = 0.458 cm^?1, and C = 0.388 cm^?1. Spin splittings for the K_a′ = 0 excited state levels fit a simple symmetric top formula and give $\text{(?}{}_{\mathrm{bb}}\text{+ ?}{}_{\mathrm{cc}}\text{)}\text{2}\text{= ?0.0483}\text{cm}{}^{\mathrm{?1}}$. Spin splittings for K_a′ = 1 (N′ even) are irregular and are shown to change sign between N′ = 6 and 8. Assuming that the large inertial defect of 4.66 amu Ų arises solely from A, a structure for the ²B₂ state is obtained which gives $\text{r}\text{(NO) = 1.35}\text{A}\text{?}$ and an ONO angle of 105°. Alternatively, weighting the three rotational constants equally gives $\text{r = 1.29}\text{A}\text{?}$ and θ = 118°.     

Inelastic scattering and satellite fine structure in the high-resolution uv photoelectron spectrum of CS2

The outer valence region in CS₂ has been studied by high-resolution UV photpelectron Spectroscopy. The spectra reveal detailed vibrational structure in the X$\text{\$}\text{?}$²Π_g, A$\text{\$}\text{?}$²Π_u, B$\text{\$}\text{?}$²Σ⁺_u and C$\text{\$}\text{?}$²Σ⁺_g bands. Some of the fine-structure peaks in the X$\text{,}\text{?}$B$\text{\$}\text{?}$and C$\text{\$}\text{?}$bands are shown to be pressure-dependent. The reason for the pressure dependence is assumed to be inelastic scattering of electrons emitted in the adiabatic transitions. It is established that the two CI satellite bands present in the He(I)-excited spectrum contain vibrational structure.     

The magnetic moment of the 4+, 3.55 MeV level of 18O

The magnetic moment of the 4⁺, 3.55 MeV level of ¹⁸O has been determined to be |g| = 0.62 ± 0.10 in a perturbed angular correlation measurement on nuclei recoiling into gas and vacuum. Analysis of the recoil-into-gas data using the Abragam-Pound model agrees with analysis of the recoil-into-vacuum data using a model for the electronic ensemble described in a previous communication. The value of the g-factor shows the 4⁺ wave function to consist mainly of the$\text{d}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}{}^2$ configuration.     

The crystal structures of the ion conductors (NH+4)Zr2(PO4)3and (H3O+)Zr2(PO4)3

The crystal structures of (NH⁺₄)Zr₂(PO₄)₃ and (H₃O⁺)Zr₂(PO₄)₃ have been determined from neutron time-of-flight powder diffraction data obtained at 15 K. Both compounds are rhombohedral, $\text{R}\text{3}\text{c}$, with cell parameters a=8.7088(1) and c=24.2197(4) Å for the ammonium compound and a=8.7528(2), c=23.6833(11) Å for the hydronium compound. In both cases the ions are completely localized in the type I cavities and hydrogen bonded to lattice oxygens. The measured unit cell parameters are relatively large for this class of compounds but the entrance ways into the cavities are still too small to allow for unrestricted movement of the ions. Thus the low conductivity of the hydronium ion is related to this and other structural features.