Synchrotron radiation induced photoionization and photodissociation of carbon monoxide in the 14–35 eV region

Abstract

Abstract. Carbon monoxide has been excited with monochromatic synchrotron radiation in the 14-35 eV range using the Swedish synchrotron facility MAX in Lund. The decay products were studied in various detection channels such as formed CO + and C + ions using mass spectroscopy and visible or VUV fluorescence using photon detection. A rich line structure is observed which is attributed to CO Rydberg series converging to the X, A, B, D, C and E states in CO +. While a great number of these lines are already known, some of them are classified here for the first time. The combination of information from the fluorescence spectra and the mass spectra contribute important information concerning the autoionization and predissociation of these various Rydberg series. 33.20.N; 33.80.E; 33.80.G have not been firmly established until recently. Thus, it is tempting to look fo r Rydberg series converging to these doubly excited states in various detection channels. Moreover, the lower Rydberg series converging to the X, A and B states of CO ÷ are very complex and fluorescence measurements could, hopefully, give additional information concerning their decay channels. To our knowledge such fluorescence studies using a continuous excitation have only been performed for emission wavelengths larger than 2100 A [3][4][5]. PACS:Since the notations of the doubly excited states in CO + vary in different papers, Table 1 shows the notations used in the present work together with very recently established level energies from photoelectron spectroscopy [6]. These notations have been introduced by some authors to make an analogy to the isoelectronic case of N~.

Photoionization and photodissociation of nitric oxide in the range 9–35 eV

“…Different Hamamatsu PM tubes were used for various wavelength regions R1080 ͑1150-3200 Å͒, R1081 ͑1150-2000 Å͒, and R647 ͑3000-6500 Å͒. This system has earlier been used in similar investigations for instance of N 2 , 28,29 O 2 , 30,31 CO, 32 and CO 2 . 33 A closer description of the experimental setup is found in Ref.…”

CO + B 2 Σ + (ν=0) emission induced by laser excitation of neutral CO at 230 nm

“…27 Using mass spectroscopy, Sha and co-workers 11 detected both C ϩ and O ϩ photofragments after 2ϩ1 REMPI of CO at 230 nm and determined the pulse-energy dependence for the corresponding photofragment yields. Their results suggest that all photodissociation channels in Eqs.…”

Preparation of Ceramics (RCa)Ba2Cu4O8 (R=Y, Ho, Er, Tm and Yb) by Conventional Solid-State Reaction

“…The undispersed VUV fluorescence in the range from 105 to 200 nm has been detected by a CsI-coated microchannel plate (MCP) behind a LiF window. Absolute wavelengths of the monochromatized SR have been calibrated by matching observed peak energies with the well known energies of some vibronic levels of Rydberg states converging to the CO + (B) state (Ogawa and Ogawa 1972, Ito et al 1985, Erman et al 1994 between 19 and 19.6 eV. PIFS spectra have been taken using a 20 cm Seya-Namioka monochromator for dispersing and a position-sensitive detector (Ukai et al 1992a) for recording the fluorescence with a typical resolution of 1.3 nm.…”

“…In Ehresmann et al (1995) the problem of assigning the different observed line structures in the cross sections to specific superexcited states of CO has been shared out and available assignments from literature have been used. However, in a very recent publication, Erman et al (1994) pointed out the necessity of a reassignment of the observed line structures. Based also on a very recently published high-resolution photoelectron study of Baltzer et al (1994) they reassigned line structures observed in their photoion spectra and their measurements of the undispersed fluorescence excitation as a function of the exciting-photon energy (FE function) to some vibrational levels of CO Rydberg states converging to the D, C, and E states of CO + .…”