Intensity measurement of laser-excited fluorescence in the B3Πu(0+)-X1Σg+ system of diatomic lodine

Fluorescence was excited in the B³Π_u(0⁺)-X¹Σ_g⁺ system of diatomic iodine by means of the 5145-Å line of an Ar⁺ laser and the 6328-Å line of a HeNe laser. The resulting spectrum was recorded on a SPEX double monochromator and a quantitative measurement of the intensities was carried out. The variation of the electronic transition moment $\text{M(}\text{R}\text{)}$ with R centroid observed by us shows a behavior similar to what has been reported earlier.     

The spectrum of HeNe+

Discharges through mixtures of helium and neon show two band groups near 4250 and 4100 Å as first observed by Druyvesteyn. These bands, assigned to the HeNe⁺ ion by Tanaka, Yoshino, and Freeman, have been studied under high resolution and have been fairly completely analyzed. The upper state of the transition is a very weakly bound state resulting from $\text{He}{}^{\mathrm{+}}\text{(}{}^2\text{S) +}\text{Ne}\text{(}{}^1\text{S}{}_0\text{)}$. There are two lower states resulting from the two components of $\text{Ne}{}^{\mathrm{+}}\text{(}{}^2\text{P) +}\text{He}\text{(}{}^1\text{S}{}_0\text{)}$. The upper of these two (${}^2\text{Π}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$) is also very weakly bound while the lower of the two, the ²Σ⁺ ground state, has a dissociation energy of 0.69 eV and an r_e value of 1.30 Å. All bands in both band groups show four branches designated R_ff, Q_ef, Q_fe, and P_ee. From their analysis the rotational constants in the various vibrational levels of the three electronic states have been determined. While no spin splitting in the B²Σ⁺ state has been found the ground state X²Σ shows a very large spin splitting and the $\text{A}{}_2{}^2\text{Π}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ state a very large $\text{Ω-type}$ doubling. The vibrational numberings in all these states were established by the study of the spectrum of ³HeNe⁺. At the same time the hyperfine structure observed in all lines of ³HeNe⁺ confirmed the nature of the upper state B²Σ⁺ as resulting from He⁺ + Ne, i.e., by charge exchange from the ground state. The ${}^2\text{Π}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ component of the ²Π state has not been observed, presumably because of low intensity.     

Analysis of the B1Πu → X1Σg+ band system of 7Li2 molecule excited by the 4545- and 5287-Å visible lines of the argon ion laser

Two new fluorescence series have been excited by the two lines at the extreme ends of the range of visible Ar⁺ transitions, 4545 and 5287 Å. In each case the B¹Π_u electronic state of ⁷Li₂ is excited, to levels $\text{v′ = 12, J′ = 13 (4545}\text{A}\text{?}\text{)}$ and $\text{v′ = 2, J′ = 58 (5287}\text{A}\text{?}\text{)}$. Fluorescence to the ground state can be detected in the range 2 ≤ v″ ≤ 23 and 0 ≤ v″ ≤ 8, respectively. Measured relative intensities agree well with calculated radiative transition probabilities reported herein.     

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.     

S-P wave interference in K+K− photoproduction near K+K− threshold

A mass-dependent asymmetry was observed in the decay angular distribution of a photoproduced K⁺K^? system near the K⁺K^? threshold. The corresponding moments 〈Y₁⁰〉 have been evaluated. Interpreting the asymmetry as an S-P wave interface due to the states S₉₉₃¹(0⁺) and ø₁₀₁₉(1^?) one can compute the moments 〈Y₁⁰〉 through an amplitude analysis. The theoretical calculation reproduces the experimental results well, if one assumes a real S-wave amplitude for the S₉₉₃¹. The data cannot be explained by a non-resonant real S-wave. Other possibilities have been discussed. An estimate of the photoproduction cross section of the $\text{S}{}^1\text{→}\text{K}{}^{\mathrm{+}}\text{K}{}^{\mathrm{?}}$ can be given on the basis of the above hypothesis.     

The g-factor difference for the 61+ and 88+ states in 210Po

The difference in g-factors for the 6₁⁺ and 8₁⁺$\text{(πh}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}{}^2\text{)}$ states in ²¹⁰Po has been measured as $\text{(g}{}_6\text{? g}{}_8\text{)}\text{g}{}_8\text{= 2.0 ± 0.7\%}$. This result represents a small violation of additivity. A value of g₈ = 0.909 ± 0.011, independent of g₆, was also obtained.     

Quadrupole moments of 81+ states in 92,94Mo

The ratio of the quadrupole moments of the 8₁⁺ states in ${}^{\mathrm{92,94}}\text{Mo}$ has been measured as $\text{Q(}{}^{94}\text{)}\text{Mo}\text{Q(}{}^{92}\text{Mo}\text{)}\text{= 1.48 ± 0.12}$ by means of the TD PAD method following the ${}^{\mathrm{90,92}}\text{Zr}\text{(α, 2}\text{n}\text{)}{}^{\mathrm{92,94}}\text{Mo}$ reactions on enriched Zr metal foils. This ratio is consistent with the effective charge ratio for the 8⁺ → 6⁺E2 transitions which demonstrates a prediction of the effective charge concept.     

Rotational analysis of the B3Π(0+) → X1Σ+ band systems of 35Cl35Cl and 35Cl37Cl in the chlorine afterglow emission spectrum

The B³Π(0⁺) → X¹Σ⁺ band system of Cl₂, excited by the recombination of ground state $\text{Cl}{}^2\text{P}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ atoms at total pressures near 2 Torr, has been rotationally analyzed in the range 6300–9900 Å. About 30 bands, with 0 ≤ v′ ≤ 6 and 5 ≤ v″ ≤ 14, were investigated, mostly for both ³⁵Cl³⁵Cl and ³⁵Cl³⁷Cl. The band origins and rotational constants for the B state were obtained with the help of the known constants for the ground state. The principal molecular constants (cm^?1) for the B³Π(0⁺) state of ³⁵Cl³⁵Cl are as follows: T_e′ = 17 817.67(3); ω_e′ = 255.38(3); ω_e′x_e′ = 4.59(1); ω_e′y_e′ = ?0.038(8); D_e′ = 3341.17(14); B_e′ = 0.16313(3); α_e′ = 2.42(3) × 10^?3; γ_e′ = ?5.7(7) × 10^?5. The equilibrium internuclear separation is 2.4311(2) Å. The results of Briggs and Norrish on a transient absorption spectrum of Cl₂ assigned as $\text{0}{}_{\mathrm{g}}{}^{\mathrm{+}}\text{← B}{}^3\text{Π}\text{(0}{}^{\mathrm{+}}\text{)}$ are reinterpreted with the present constants.     

An experimental study of the form factor in the decay K+ → πoe+ν

The q² variation of the factor $\text{?}{}_{\mathrm{+}}\text{(q}{}^2\text{)}$ in the decay K⁺→π⁰e⁺ν has been studied using a sample of even detected in the CERN 1.1 m³ heavy-liquid bubble chamber. The data are consistent with a linear development $\text{?}{}_{\mathrm{+}}\text{(q}{}^2\text{)=?}{}_{\mathrm{+}}\text{(0) (1+λ}{}_{\mathrm{+}}\text{q/m}{}^2{}_{\mathrm{\pi }}\text{)}$ with λ₊=0.027±0.008.     

Transition moment variation in the A2Σ+ → X2Πi transition of HCl+, DCl+ and HBr+

Relative emission intensities of sixteen bands of HCl⁺ (A²Σ⁺ - X²Π_i), four bands of DCl⁺ (A²Σ⁺ - X²Π_i), and 5 bands of HBr⁺ (A²Σ - X²Π_i) have been made using both ion-beam excitation and microwave discharge sources. Intensities were determined by comparison with computer-generated spectra. Treatment of the data within the r-centroid approximation shows that in HCl⁺ the electronic transition moment decreases strongly at large $\text{r}{}_{\mathrm{v\prime v″}}$ [$\text{Re}\text{α}\text{exp}\text{(?3.6}\text{r}{}_{\mathrm{v\prime v″}}\text{)}\text{for 1.44}\text{A}\text{?}\text{< r}{}_{\mathrm{v\prime v″}}\text{< 1.82}\text{A}\text{?}$] but levels off at shorter $\text{r}{}_{\mathrm{v\prime v″}}$. DCl⁺ data agree quantitatively with HCl⁺. The variation in the HBr⁺ moment is similar, with $\text{R}\text{e}\text{α}\text{exp}\text{[?4.5}\text{r}{}_{\mathrm{v\prime v″}}\text{]}\text{for 1.58}\text{A}\text{?}\text{<}\text{r}{}_{\mathrm{v\prime v″}}\text{< 1.78}\text{A}\text{?}$.     

The QCD effective coupling constant in e+e− annihilation

The QCD effective coupling constant α_s(Q²) is determined by comparing the O(α_s)² jet-distributions with the high-energy e⁺e^? data from PETRA. We get α_s(Q² = 1225 GeV²) = 0.125 ± 0.01, which corresponds to $\text{Λ}{}_{\mathrm{<mtext>MS</mtext>}}\text{= 110}{}^{\mathrm{+70}}{}_{\mathrm{?50}}\text{MeV}$ with five flavours.     

The spectrum of HeAr+

Two band groups near 1450 Å, first observed by Tanaka, Yoshino, and Freeman (J. Chem. Phys.62, 4484–4496 (1975)) in discharges through mixtures of helium and argon and assigned by them to the HeAr⁺ ion, were studied under high resolution. Like the similar spectrum of HeNe⁺ previously investigated, the spectrum of HeAr⁺ is a charge transfer spectrum. The upper state B²Σ⁺ of both band groups is derived from $\text{He}{}^{\mathrm{+}}\text{(}{}^2\text{S) +}\text{Ar}\text{(}{}^1\text{S)}$ while the two lower states $\text{A}{}_2{}^2\text{Π}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ and X²Σ⁺ are derived from $\text{He}\text{(}{}^1\text{S) +}\text{Ar}{}^{\mathrm{+}}\text{(}{}^2\text{P)}$. All three states are very weakly bound, the two lower states even more weakly than the upper state. Unlike HeNe⁺ most of the HeAr⁺ bands are violet shaded. In the longward band group each band shows only three branches while in the shortward group there are four. The former observation shows that the $\text{A}{}_2{}^2\text{Π}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ state behaves like a ²Σ^? state with γ_v ≈ 0. The B, D, γ, p, and ΔG values of all states were evaluated. While the B_v values of upper and lower states are nearly equal, the D_v values are quite different and this difference accounts for the violet shading of most of the bands even when B′_v is slightly smaller than B″_v; it also accounts for some of the extraheads and linelike features in the rotational structure. As in HeNe⁺ the ${}^2\text{Π}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ component of ²Π was not observed.     

Neutron scattering study of NH4+ Motion in NH4+ β-alumina

Incoherent inelastic neutron scattering has been used to study the motion of NH₄⁺ ions in NH₄⁺ β-alumina. The results establish that jump reorientation of NH₄⁺ ions is rapid compared to translational diffusion: The data are consistent with thermally activated jumps between equivalent NH₄⁺ orientations with a proton jump frequency of $\text{~1.0 × 10}{}^{12}\text{sec}$ at room temperature.The data are inconsistent with either free rotation or unrestricted rotational diffusion. The residence time between translational diffusion jumps is >6 × 10^?11 sec at temperatures less than 473°K.     

The ionic distribution in Mn2+ and Zn2+ β″-alumina

The ionic distributions in Mn²⁺ and Zn²⁺ β″-alumina (idealized formula: $\text{X}{}_{\mathrm{<mtext>5</mtext><mtext>6</mtext>}}\text{Mg}{}_{\mathrm{<mtext>2</mtext><mtext>3</mtext>}}\text{Al}{}_{\mathrm{<mtext>31</mtext><mtext>3</mtext>}}\text{O}{}_{17}\text{;}\text{X}\text{=}\text{Mn}\text{and}\text{Zn}\text{)}$ at 296 K are reported from single-crystal X-ray diffraction studies. Mn²⁺ β″-alumina exhibits the shortest c-axis found so far in any divalent β″-alumina: 33.141(3) Å;Zn²⁺ β″-alumina, which involves the smallest divalent ion studied in the frame-work, has a considerably longer c-axis: 33.517(3) Å. Both compounds show clear evidence of short-range correlation effects in the X²⁺ ion arrangement by way of departures from the centrosymmetric space-group $\text{R}\text{3}\text{m}$ of the β″-skeleton. Both 6c end-sites and 9d mO-sites ($\text{R}\text{3}\text{m}$ notation) are occupied for both ion-types, a significantly larger occupation (60% compared to 28% of the total) lying at or near the 9d mid-oxygen sites in Mn²⁺ β″-alumina compared to Zn²⁺ β″-alumina. Disorder is also found in the column-oxygen O(5) in both cases; the O(5) displacement from the 3b site in Mn²⁺ β″-alumina (0.59 Å) is the largest found in any divalent β″-alumina. The formula-unit/cell-layer, deduced on the basis of the amounts of X²⁺ ions refined, and assuming charge compensation through Mg substitution alone, are: Mn_0.79Mg_0.57Al_10.43O₁₇ and Zn_0.87Mg_0.74Al_10.26O₁₇.     

Polarization spectroscopy of the E0g+-B0u+ band system of Br2

The E-B (0_g⁺-0_u⁺) band system of Br₂ has been investigated at Doppler-limited resolution using polarization labeling spectroscopy. Merged E state data for the three naturally occurring isotopes in the range v_E = 0–16, expressed in terms of the constants for ⁷⁹Br₂, are (in cm^?1) Y_0,0 = 49 777.962(54), Y_1,0 = 150.834(22), Y_2,0 = ?0.4182(28), Y_3,0 = 6.6(11) × 10^?4, Y_0,1 = 4.1876(28) × 10^?2, Y_1,1 = ?1.607(16) × 10^?4, and Y_0,2 = 1.39(39) × 10^?8. The bond distance is $\text{r}{}_{\mathrm{<mtext>e</mtext>}}\text{= 3.194}\text{A}\text{?}$, and the diabatic dissociation energy to $\text{Br}{}^{\mathrm{+}}\text{(}{}^3\text{P}{}_2\text{) +}\text{Br}{}^{\mathrm{?}}\text{(}{}^1\text{S}{}_0\text{)}\text{is 34 700 cm}{}^{\mathrm{?1}}$.     

Strong sequential transfer processes in 0+ → 0+ (p,t) reactions on Pb isotopes

A marked difference of experimental analyzing powers $\text{A (θ)}\text{for}{}^{208}\text{Pb}\text{(}\text{p}\text{,}\text{t}\text{)}{}^{206}\text{Pb}\text{(0}{}_{\mathrm{<mtext>g</mtext>}}{}^{\mathrm{+}}\text{and}\text{0}{}_2{}^{\mathrm{+}}\text{)}$ reaction is explained by considering sequential transfer as wesses as well as the one-step process. The calculated A(0θ) for the 0₂⁺ state is very sensitive to the wave functions employed. An enhancement of the cross sections for the ground-state transitions of three Pb isotopes is found to be due to sequential transfer processes.     

Evidence for a narrow peak in Ksoπ±π+π- at 2.6 gev in 12 gev/cpp interactions

We report the evidence for a narrow charged peak (5.5 s.d.), which we suggest calling the I, in the 6-prong-V⁰ topology of $\text{p}$p interactions at 12 GeV/c. The mass, widht and the product of cross section σ_I times the branching ratio BR into the final state (K_s^oτ±τ⁺τ^? are found to be: $\text{M}{}_{\mathrm{I}}\text{=2.60 ±}\text{0.01}\text{GeV}\text{/}\text{c}{}^2$, $\text{Γ}{}_{\mathrm{I}}\text{?}\text{0.018}\text{GeV}\text{/}\text{c}{}^2$, σ_I·BR≈20 μbarn     

Magnetic field dependent optical dephasing in LaF3:Er3+

Optical dephasing of the 5388 Å transition between the lowest Kramers doublets of the ⁴S_{$\text{3}\text{2}$} and ⁴I_{$\text{15}\text{2}$} multiplets of Er³⁺:LaF₃ has been studied by photon echo, optical phase switching and optical free induction decay. Er³⁺?¹⁹F hyperfine interactions produce dephasing which is two orders of magnitude faster than in previously studied non-Kramers systems, but at high field changes in the spin dynamics result in microsecond dephasing. For the lower Zeeman component of ⁴S_{$\text{3}\text{2}$}, T₂ (=6μs) is independent of H₀ whereas for the upper component the dephasing is rapid and strongly field dependent. This is quantitatively accounted for by spin lattice relaxation of the upper component of ⁴S_{$\text{3}\text{2}$}. Below 20 kG concentration and temperature dependent dephasing due to electron spin diffusion is observed.     

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.     

Half-lives of two-neutron-hole O2+ states in 206Pb and 208Po

Half-lives of O₂⁺ states in ²⁰⁶Pb and ²⁰⁸Po, 770±40 and 465±20ps, respectively, are determined using direct-timing techniques. The corresponding monopole strength parameter values,$\text{ρ(}{}^{206}\text{Pb}\text{) = 0.034±0.002}$ and $\text{ρ(}{}^{208}\text{Po}\text{)=0.030?0.037}$, indicate that the O₂⁺ states in both nuclei are mainly of similar two-neutron-hole character.