The E(2)Sigma(+) --> C(2)Pi Transition of NO and Term Values for the A, D, E, and C Lowest Rydberg Levels

The E(2)Sigma(+) --> C(2)Pi Rydberg-Rydberg transition of (14)N(16)O near 8492 cm(-1) has been studied by Fourier transform spectrometry in the emission from a dc excited supersonic jet expansion and from a dc discharge under equilibrium conditions. The same transition has also been observed in laser-induced stimulated emission. Line wavenumbers of the 0-0, 1-1, and 2-2 bands, together with data for previously published near-infrared transitions, have been reduced to consistent sets of rovibronic term values for v = 0, 1, and 2 of the A(2)Sigma(+), D(2)Sigma(+), E(2)Sigma(+), and C(2)Pi states which frequently serve as intermediates in the multiphoton excitation of higher Rydberg levels of NO. Copyright 2000 Academic Press.     

Anomalously hindered E2 strength B(E2;2+(1)-->0+) in 16C

The electric quadrupole transition from the first 2(+) state to the ground 0(+) state in 16C is studied through measurement of the lifetime by a recoil shadow method applied to inelastically scattered radioactive 16C nuclei. The measured mean lifetime is 77+/-14(stat)+/-19(syst) ps. The central value of mean lifetime corresponds to a B(E2;2+(1)-->0(+)) value of 0.63e(2) fm(4), or 0.26 Weisskopf units. The transition strength is found to be anomalously small compared to the empirically predicted value.     

Observation/confirmation of hindered E2 strength in 18C/16C

We have measured the lifetime of the first excited 2⁺ state in ¹⁸C using an upgraded recoil shadow method to determine the electric quadrupole transition. The measured mean lifetime is 18.9±0.9 (stat)±4.4 (syst) ps, corresponding to B(E2;2₁ ⁺ $ \rightarrow$ 0⁺ _gs) = 4.3±0.2±1.0e ² fm^4, or about 1.5 Weisskopf units. The mean lifetime of the first 2⁺ state in ¹⁶C was remeasured to be 18.3±1.4±4.8 ps, about four times shorter than the value reported previously. The discrepancy is explained by incorporating the $ \gamma$ -ray angular distribution obtained in this work into the previous measurement. The observed transition strengths in ^{16, 18}C are hindered compared to the empirical values, indicating that the anomalous E2 strength observed in ¹⁶C persists in ¹⁸C .     

Streuwirkungsquerschnitte12C(p,p)12C undl2C(d,d)12C im EnergiebereichE p=350...550 keV,bzw.E d=600...1100 keV

Scattering Cross Sections¹²C(p, p)¹²C and^l2C(d, d)¹²C in the Energy Range E_p=350...550 keV resp. E_d=600...1,100 keV For an application in a work in nuclear solid state physics (elastic recoil detection with fast¹²C-ions) the scattering cross sections were measured. When adapting excitation functions with a Breit-Wigner formalism it was found that a satisfactory adaptation needed the reduction of one hard-sphere phase by the factor 0.4, and smaller, in order to maintain a reasonable value of the interaction radius.     

Comment on ‘adsorption of hydrogen on thin fcc-iron films grown on Cu(100) by C. Egawa, E.M. McCash and R.F. Willis’

In a recent Letter Egawa et al. [Surf. Sci. 215 (1989) L271] presented a detailed study of hydrogen adsorption on ultrathin iron films on the Cu(100) surface. They found the surface to reconstruct upon hydrogen adsorption and pointed out the analogy to a reconstruction reported in our previous Letter [Phys. Rev. Lett. 60 (1988) 2741]. In this Letter we present evidence that the cited reconstruction is a genuine feature of the clean iron films and is not caused by hydrogen adsorption.