Interaction strength and shape difference for the h9/2 and h11/2 configurations in163Tm

The strongly shape driving πh_9/2[541]l/2^? configuration with α=+1/2 exhibits some anomalous, and so far unexplained, features concerning the crossing frequency, ?ω_c, the aligned angular momentum, i_x, and interaction strength, at the alignment of the first pair of i_13/2 quasineutrons in several odd-Z rare earth-nuclei. The h_9/2[541]1/2^? and h_11/2[523]7/2^? bands have been studied in the stably deformed rare-earth nucleus¹⁶³Tm to investigate these features. A difference in band crossing frequency of ～ 80 keV between the two bands is found. Rotational bands built on these two configurations have been found to cross in the spin range I=25/2–29/2 ?. Theγ-decay pattern between the two bands is established in the crossing region and analysed in terms of a moderate shape difference between them. A theoretical estimate of the size of the interaction strength between the two bands is presented and compared to the experimental value. The observed band structure in¹⁶³Tm is very similar to that of¹⁶⁷Lu which has 2 protons and 2 neutrons in addition. This observation is discussed in relation to the similarity of the yrast bands of the two even-even “core” nuclei¹⁶²Er and¹⁶⁶Yb, for which theγ-transition energies are identical within ～0.2 keV below the vi_13/2 crossing.     

Influence of a strong proton-neutron interaction on mass 100 nuclei and properties of the octupole two-phonon multiplet in96Zr

Experimental evidence, which suggests a strong proton-neutron interaction giving rise to deformation and influencing the deformation properties of mass 100 nuclei, is reviewed, as is the large variation in the interaction strength for N=59 isotones and for coexisting states of 46≤Z≤54 isotones. Properties of the recently discovered octupole two-phonon multiplet in⁹⁶Zr are presented, compared to spdf-boson IBM calculations, and consequences of its fragmentation are discussed.     

Competition between (h11/2)2 proton and neutron excitations around128Ba: Coexistence of near prolate and near oblate shapes at high spin

Recent cranked shell model calculations give a possible explanation for the occurrence of two S-bands in Ba-nuclei.     

The need for a state dependent interaction in proton inelastic scattering from 24Mg

The calculated angular distributions for proton elastic and inelastic scattering can be greatly improved by using an imaginary potential which depends upon the nuclear state. We demonstrate that this is just the effect expected from the coupling of deuteron channels and the phenomenon therefore provides a signature for multistep processes which is not dependent on detailed calculations. The obvious application to the usual DWBA calculations of inelastic proton scattering is mentioned.     

Study of strong interaction between Pt and TiO2 under oxidizing atmosphere

The strong interaction between Pt and TiO₂ under oxidizing atmosphere was studied by means of X-ray photoelectron spectroscopy (XPS) and Ar⁺ sputtering test. The results obtained show that under oxidizing atmosphere Pt⁰ atoms can thermally diffuse into TiO₂ lattice and be oxidized to Pt²⁺ to substitute for Ti⁴⁺ or form the interstitial ions at 673 K.     

Evidence for the negative s-f interaction in a noble metal host

Electrical resistivity measurements on dillute alloys of Ce, Gd and Yb in Au are reported. Both Ce and Gd alloys show negligible temperature dependence in their excess resistivity at low temperatures whereas the Kondo effect is unambigously observed in the case of $\text{Au}\text{Yb}$. This result correlates with a negative exchange constant found for $\text{Au}\text{Yb}$ in the EPR experiment of Tao and co-workers.     

Knight shifts and absolute magnetic moments of (h9/2) n proton states in trans-bismuth nuclei

The Knight shiftsK(FrT1) andK(RaPb) have been measured in connection with a systematic study on magnetic moments of (h_9/2) ⁿ proton states. The Knight shifts were obtained directly by a comparison of precession frequencies and, indirectly, from relaxation times involving the Korringa relation. Good agreement is found among the results from the different methods; the average values areK(FrT1)=(0.89±0.09)% andK(RaPb)=(1.05±0.15)%.     

He2 and HeH molecular ions in a strong magnetic field: The Lagrange-mesh approach

Accurate calculations for the ground state of the molecular ions He³⁺₂ and HeH²⁺ placed in a strong magnetic field B?10² a.u.$B?{10}^2\text{a.u.}$ (≈2.35×10¹¹ G$\approx 2.35\times {10}^{11}\text{G}$) using the Lagrange-mesh method are presented. The Born–Oppenheimer approximation of zero order (infinitely massive centers) and the parallel configuration (molecular axis parallel to the magnetic field) are considered. Total energies are found with 9–10 s.d. The obtained results show that the molecular ions He³⁺₂ and HeH²⁺ exist at B>100 a.u.$B>100\text{a.u.}$ and B>1000 a.u.$B>1000\text{a.u.}$, respectively, as predicted in Turbiner and López Vieyra (2007) [1] while a saddle point in the potential curve appears for the first time at B∼80 a.u.$B\sim 80\text{a.u.}$ and B∼740 a.u.$B\sim 740\text{a.u.}$, respectively.     

Spin and magnetic moment of 33Mg: evidence for a negative-parity intruder ground state

We report on the first determination of the nuclear ground-state spin of 33Mg, I=3/2, and its magnetic moment, mu= -0.7456(5) mu(N), by combining laser spectroscopy with nuclear magnetic resonance techniques. These values are inconsistent with an earlier suggested 1 particle-1 hole configuration and provide evidence for a 2 particle-2 hole intruder ground state with negative parity. The results are in agreement with an odd-neutron occupation of the 3/2 [321] Nilsson orbital at a large prolate deformation. The discussion emphasizes the need of further theoretical and experimental investigation of the island of inversion, a region previously thought to be well understood.     

Evidence for bicarbonate formation on vacuum annealed TiO2(110) resulting from a precursor-mediated interaction between CO2 and H2O

The reaction of CO₂ and H₂O to form bicarbonate (HCO⁻₃) was examined on the nearly perfect and vacuum annealed surfaces of TiO₂(110) with temperature programmed desorption (TPD), static secondary ion mass spectrometry (SSIMS) and high resolution electron energy loss spectrometry (HREELS). The vacuum annealed TiO₂(110) surface possesses oxygen vacancy sites that are manifested in electronic EELS by a loss feature at 0.75 V. These oxygen vacancy sites bind CO₂ only slightly more strongly (TPD peak at 166 K) than do the five-coordinated Ti⁴⁺ sites (TPD peak at 137 K) typical of the nearly perfect TiO₂(110) surface. Vibrational HREELS indicates that CO₂ is linearly bound at the latter sites with a ν_a(OCO) frequency similar to the gas phase value. In contrast, oxygen vacancies dissociate H₂O to bridging OH groups which recombine to liberate H₂O in TPD at 490 K. No evidence for a reaction between CO₂ and H₂O is detected on the nearly perfect surface. In sequentially dosed experiments on the vacuum annealed surface at 110 K, CO₂ adsorption is blocked by the presence of preadsorbed H₂O, adsorbed CO₂ is displaced by postdosed H₂O, and there is little or no evidence for bicarbonate formation in either case. However, when CO₂ and H₂O are simultaneously dosed, a new CO₂ TPD state is observed at 213 K, and the 166 K state associated with CO₂ at the vacancies is absent. SSIMS was used to tentatively assign the 213 K CO₂ TPD state to a bicarbonate species. The 213 K CO₂ TPD state is not formed if the vacancy sites are filled with OH groups prior to simultaneous CO₂+H₂O exposure. Sticking coefficient measurements suggest that CO₂ adsorption at 110 K is precursor-mediated, as is known to be the case for H₂O adsorption on TiO₂(110). A model explaining the circumstances under which the proposed bicarbonate species is formed involves the surface catalyzed conversion of a precursor-bound H₂O–CO₂ van der Waals complex to carbonic acid, which then reacts at unoccupied oxygen vacancies to generate bicarbonate, but falls apart to CO₂ and H₂O in the absence of these sites. This model is consistent with the conditions under which bicarbonate is formed on powdered TiO₂, and is similar to the mechanism by which water catalyzes carbonic acid formation in aqueous solution.