Parity Of Ground State Research Articles

Excited states and electrochromism of radical cation of the carotenoid astaxanthin

Radical cations of the carotenoid astaxanthin were generated by chemical oxidation with Fe(Cl) 3, and their absorption and electroabsorption (Stark) spectra at temperatures about 150 K were recorded in the spectral range from 5900 to 26000 cm −1 (380 to 1700 nm), covering two absorptive electronic transitions from D 0 (ground) to D 1 and D 2 excited states. The changes in static polarizability are negative and equal −40±10 A 3 for D 0→D 1 and −105±15 A 3 for D 0→D 2, pointing that dominant contribution to polarizabilities results from the coupling of D 1 and D 2 with the ground state. An approximate localization of the next excited state with ground-state parity is estimated based on arguments from perturbation theory.

Coherent control of molecular orientation

A coherent control scheme is proposed for the orientation of heteronuclear molecules by two-color phase-locked laser excitation. In the case of hexapole state-selected NO, a superposition of both negative and positive ground-state parity levels is formed, where the internuclear axis of the molecule is oriented along the laser polarization axis. The proposed scheme allows rotationally cold distributions of ground-state heteronuclear molecules to be macroscopically oriented, as in the “brute force” dc electric field orientation technique. Computer simulations show that for a typical 1 Σ ground-state diatomic molecule ( B rot = 0.32 cm −1) picosecond two-color phase-locked laser excitation can provide orientation during or after the laser pulse.

Long-lived isomers in 190Ir

Long-lived isomeric states in 190Ir have been investigated with the 192Os(p,3n) 190Ir and 192Os(d,4n) 190Ir reactions using beams of 18–31 MeV protons and 27.8 MeV deuterons, respectively. A series of measurements, including excitation functions, half lives, e − γ coincidences and e − e − coincidences, was performed. Five new transitions were observed, and the results of e − γ and e − e − coincidences indicate that these transitions are fed by the 148.7 keV M4 transition that depopulates the 11 − isomer. The previous decay scheme is shown to be incorrect, and the results allow the ground state parity and mass excess to be determined.

Fluorescence depletion spectroscopy of the CH/D–Ne B 2Σ−–X 2Π transition

Fluorescence depletion techniques were used to test vibronic and rotational assignments for the B 2Σ−–X 2Π transition of CH–Ne. Previous vibronic assignments [W. H. Basinger, U. Schnupf, and M. C. Heaven, Faraday Discuss. 97, 351 (1994)] were confirmed, and observations of transitions to dissociation continua provided accurate dissociation energies for the B and X states. Errors in the rotational assignments were discovered. Re analysis of the rotational structure yielded ground state parity splittings and improved rotational constants. Adiabatic model calculations were used to determine approximate angular potential energy curves for the B and X states. These calculations also accounted for the prominent optical activity of internal rotation in the spectrum.

Nuclear data sheets for A = 153

The present work presents a compilation of experimental data on nuclides with mass number A = 153. This compilation constitutes an updating of the previous A = 153 data compilation which appeared in the Nuclear Data Sheets in November 1963. The cutoff date for the data included in this compilation is approximately June 1, 1972. Data are included for 9 nuclides, 153Pm(Z = 61) through 153Tm(Z = 69). Direct measurements of the ground-state spins now exist for the Z = 62 through Z = 66 members of this A-chain. Changed from the 1963 version are the ground-state parity assignments for 153Sm and 153Gd, given here as π = + for 153Sm and π = − for 153Gd. The availability of data from high-resolution neutron-capture γ-ray spectroscopy, single-nucleon-transfer reactions, and (α,xn) reactions since the last compilation has provided a much more complete picture of the energy-evel structure of these nuclei. Based on the present data, there is evidence for well-developed rotational-band structure in 153Sm and 153Eu. In these cases, energy-level systematics are treated in terms of the Nilsson model including various well-established couplings. While well-developed rotational-band structure is also observed in 153Gd, suggesting the existence of a deformed equilibrium shape, attempts to make configuration assignments to some of the lower lying states in terms of a deformed-nucleus coupling scheme have encountered serious difficulties. In addition, it has not yet been possible to provide an interpretation of all the currently available data on the energy levels above approximately 0.4 MeV in 153Eu in terms of the expected single-particle and vibrational configurations. An attempt has been made to provide absolute β- and γ-branching ratios on the decay-scheme drawings. In 153Sm β-decay, where two essentially independent types of measurements for determining β-branching ratios exist and give consistent results, the β- and γ-branching ratios are considered well established. In the β-decay of 153Pm and the ε-decay of 153Gd, 153Tb, and 153Dy it has been necessary to rely on indirect means to estimate branching ratios. The methods employed to do this are discussed in connection with the specific nuclides.

Ground state parity of 227Ac

The K-shell internal conversion coefficient and L-subshell electron ratios were measured for the transition from the 3 2 − 327 keV level to the I = 3 2 ground state in 227Ac. The results indicate that the transition is an M1 + E2 multipole mixture. Thus, the 277Ac ground-state parity is odd.

The Ground-State Parity ofN14

Four-Mev deuterons from the Rochester 27-inch cyclotron have been used to determine the angular distribution of the neutrons from the ${\mathrm{C}}^{13}(d,n){\mathrm{N}}^{14}$ ground-state reaction for laboratory angles less than 45\ifmmode^\circ\else\textdegree\fi{}. Similar measurements have been made on the ${\mathrm{Be}}^{9}(d,n){\mathrm{B}}^{10}$ and ${\mathrm{F}}^{19}(d,n){\mathrm{Ne}}^{20}$ ground-state reactions, primarily to confirm the applicability of the Butler stripping theory at this energy and with this particular experimental arrangement. Comparison of the experimental results with the predictions of the theory shows that there is a parity change in the ${\mathrm{C}}^{13}(d,n){\mathrm{N}}^{14}$ and ${\mathrm{Be}}^{9}(d,n){\mathrm{Ne}}^{20}$ reactions and no parity change in the ${\mathrm{F}}^{19}(d,n){\mathrm{Ne}}^{20}$ reaction. Since the ${\mathrm{C}}^{14}$ and ${\mathrm{C}}^{13}$ ground states have been previously shown to have opposite parity, there can be no parity change in the ${\mathrm{C}}^{14}$ beta-decay.