Arup Sinha

Contrasting reactivity of 2-mesityl-1,8-naphthyridine (Mes-Np) with singly-bonded [Rh II Rh II ] and [Ru I –Ru I ] compounds

Reaction of cis-[Rh2(CH3COO)2(CH3CN)6](BF4)2 with two equivalents of 2-mesityl-1,8-naphthyridine (Mes-NP) affords trans-[Rh2(CH3COO)2(Mes-NP)2](BF4)2 (1). X-ray structure reveals weak Rh–C(ipso) interaction, and a short Rh–Rh distance. The same ligand, in contrast, oxidatively cleaves the Ru–Ru bond in cis-[Ru2(CO)4(CH3CN)6](BF4)2 and results in trans-[Ru(Mes-NP)2(CH3CN)2](BF4)2 (2). Both compounds adopt trans geometry to relieve the steric strain. Compound 2 exhibits moderate activity for the alcohol oxidation and aldehyde olefination reactions.

Shape coexistence inHo153

The high-spin states in 153Ho, have been studied by 139 57 La(20Ne, 6n) reaction at a projectile energy of 139 MeV at Variable Energy Cyclotron Centre (VECC), Kolkata, India, utilizing an earlier campaign of Indian National Gamma Array (INGA) setup. Data from gamma-gamma coincidence, directional correlation and polarization measurements have been analyzed to assign and confirm the spins and parities of the levels. We have suggested a few additions and revisions of the reported level scheme of 153Ho. The RF-gamma time difference spectra have been useful to confirm the half-life of an isomer in this nucleus. From the comparison of experimental and theoretical results, it is found that there are definite indications of shape coexistence in this nucleus. The experimental and calculated lifetimes of several isomers have been compared to follow the coexistence and evolution of shape with increasing spin.

High-spin structure and band termination in {sup 103}Cd

Excited states of the neutron-deficient {sup 103}Cd nucleus have been investigated via the {sup 72}Ge({sup 35}Cl, p3n) reaction at beam energy of 135 MeV by use of in-beam spectroscopic methods. Gamma rays depopulating the excited states were detected using the Gammasphere spectrometer with high-fold {gamma}-ray coincidences. A quadrupole {gamma}-ray coincidence analysis ({gamma}{sup 4}) has been used to extend the known level scheme. The positive-parity levels have been established up to J=35/2({Dirac_h}/2{pi}) and E{sub x}=7.071 MeV. In addition to the observation of a highly fragmented level scheme belonging to the positive-parity sequences at E{sub x}{approx}5 MeV, the termination of a negative-parity sequence connected by E2 transitions has been established at J=47/2({Dirac_h}/2{pi}) and E{sub x}=11.877 MeV. The experimental results corresponding to both the positive- and negative-parity sequences have been theoretically interpreted in the framework of the core particle coupling model. Evidence is presented for a shape change from collective prolate to noncollective oblate above the J{sup {pi}}=39/2{sup -} (8011-keV) level and for a smooth termination of the negative-parity band.

High spin states in {sup 139}Pm

The odd mass nucleus {sup 139}Pm has been studied to high spins through the {sup 116}Cd({sup 27}Al,4n){sup 139}Pm reaction at an incident beam energy of 120 MeV. The de-exciting {gamma}-rays were detected using an array of 12 Compton suppressed Ge detectors. A total of 46 new levels have been proposed in the present work as a result of the observation of 60 new {gamma}-rays. Four new bands including a {delta}J=1 sequence have been identified and all the earlier reported bands, other than the yrast band, have been extended to higher spins and excitation energy. The spin assignments for most of the newly reported levels have been made using the observed coincidence angular anisotropy. Tilted axis cranking calculations support the interpretation of two of the observed magnetic dipole sequences as examples of magnetic rotational bands.

Erratum: Level structure of {sup 103}Ag at high spin [Phys. Rev. C 77, 024305 (2008)]

The excitation energy of the first excited level (9/2+) in 103Ag is 27.6 keV. In Table I of the article this was reported to be 10 keV. This leads to all the excitation energy being higher by 17.6 keV, so the second column of the Table I (of the earlier article) is to be replaced by the new Ex as given in the corrected Table I and Table II. The results and conclusion of the article remains unaffected.