İbrahim Okur

(e, 2e) experiments on (2s2)1S, (2p2)1D and (2s2p)1P autoionizing levels of helium in the direction of the binary lobe

The (e, 2e) triple differential cross sections are measured for the electron-impact excitation of the (2s2)1S, (2p2)1D and (2s2p)1P autoionizing transitions in helium. The experiments were performed under coplanar asymmetric kinematics, at an incident electron energy of 250 eV, and for a scattered electron detection angle of −13° in the direction of the binary lobe. The results are compared with the two available experimental data sets under similar kinematical conditions, consequently removing questions raised by the theory on these earlier results. We present evidence that the spectrum for the (2p2)1D and (2s2p)1P states might be dependent on the energy resolution of the scattered-electron energy analyser, especially in the binary region, where the strong interference between the two processes results in the observed broad asymmetric profiles. This possible distortion is not solely related to the present work.

Electron impact double-excitation of helium 2ℓ2ℓ' autoionizing states using the (e, 2e) technique

Coplanar (e, 2e) triple differential cross sections (TDCS) measurements are reported for the helium autoionizing doubly excited states, (2s2)1 S, (2p2)1D, and (2s2p)1P, for an incident electron energy of 250 eV and a scattering angle of −13°, corresponding to a momentum transfer of 1.06 a.u. The presence of autoionization results in a clearly visible recoil peak in the TDCS structure with a shape that is strongly dependent on the orbital angular momentum L of the resonance. The resonance contributions together with the strong background of direct ionization processes lead to a complicated asymmetric structure of the resonance profile in the TDCS.

AN INFRARED SPECTROSCOPIC STUDY ON A DIVALENT METAL SALT OF p-AMINOBENZOIC ACID [ABA(Mg)] TETRACYANONICKELATE

ABSTRACT Infrared spectra of MLNi (CN)4 [M=Mn, Fe, Co, Ni, Zn or Cd and L= Divalent metal of p-Aminobenzoic Acid or ABA (Mg)] are reported. Their structure consists of polymeric layers of [M-Ni(CN)4]a with the divalent metal of p-aminobenzoic acid [ABA(Mg)] molecules bound directly to the metal (M).