Photoelectron Spectra Of CO Research Articles

Cluster expansion of the wavefunction. Outer- and inner-valence ionization spectra of CS2 and COS

Abstract The ionization spectra of CS 2 and COS are calculated by the SAC Cl theory for both the outer- and the inner-valence region. The theoretical spectra compare well with the Mg Kα and He II photoelectron spectra, as well as the previous results for CO 2 . In the inner-valence region, the theoretical spectra consist of a large number of peaks due to a mixing between single ionizations and simultaneous ionization—excitation (shake-up) configurations. Assignments of the observed spectra and explanations of the origins of the similarities and differences in the photoelectron spectra of CO 2 , CS 2 and COS are given. The important role of four-electron excited configurations in addition to three-electron ones, which are included as unlinked terms in the SAC Cl theory, is indicated.

Cluster expansion of the wavefunction, valence and rydberg excitations, ionizations, and inner-valence ionizations of CO 2 and N 2O studied by the sac and sac CI theories

Valence and Rydberg excitations, ionizations, and inner-valence ionizations of CO 2 and N 2O, which are isoelectronic, are studied by the SAC and SAC CI theories. We have given a systematic assignment of the electronic spectra of these molecules, though there were some controversial situations in the assignment of the spectra. The broad and overlapping features of the spectra of the inner-valence ionizations are due to the existence of a large number of ionization-excitation states mixing with the singly ionized states. The theoretical origins of the similarities and differences in the photoelectron spectra of CO 2 and N 2O are clarified.

On the origin of satellite peaks in valence photoemission from CO ON Cu(110)

The valence-level photoelectron spectrum of CO absorbed on copper surfaces exhibits extra features in the region 10–20 eV below E F which are attributed to multielectron excitations. We have recorded the satellite intensity as a function of photon energy in the system CO/Cu(110) using synchrotron radiation. It is found that the occurrence of all satellites, including some which are observed for the first time, can be explained in terms of the SCF Xα SW model calculations by Messmer et al.

Interpretation of satellite structure in the x-ray photoelectron spectra of CO adsorbed on Cu(100)

Abstract : By employing the X alpha-scattering wave method with a Cu9CO cluster to model the chemisorption of CO on a one-fold site of a Cu(100) surface, a simple interpretation of the satellite structure observed in the x-ray photoelectron spectrum (XPS) in the C1s and O1s regions, has been obtained. The physical model obtained by analyzing the results of the Cu9CO cluster calculations is qualitatively the same as that obtained in a previous study of a CU5CO cluster with the CO in a four-fold site (Solid State Comm. 36, 265 (1980)). The quantitative differences suggest that the present Cu9CO cluster is the better model, however. Experimentally, a three peak structure is observed in both the O1s and C1s hole spectra. The 'first' peak, at lowest binding energy, is followed by a second peak at 2-3 eV higher binding energy and the third peak is at 7-8 eV higher binding energy with respect to the first peak.

Electronic structure of some methinyltricobalt enneacarbonyls by means of ultraviolet photoelectron spectroscopy

The He(I) excited photoelectron spectra of Co 3(CO) 9CY (where Y  CH 3, F, Cl) are presented, and assignments of the bands to the ionization events are made on the basis of qualitative arguments. The photoelectron data agree with the representation of this cluster as an electron sink capable of π-interaction with the substituent Y.

A high throughput 2 m normal incidence monochromator for surf-II

The high intrinsic brightness of the circulating electron beam at SURF-II is used as the entrance slit for a two-meter normal incidence monochromator. A typical beam size for the electron beam is 100 μ high by 2 mm wide yielding an observed resolution of 0.4 Å with a 200 μm exit slit and a 2400 lines/mm grating. The instrument accepts a beam with a 65 mrad horizontal divergence and a 10 mrad vertical divergence. A plane pre-mirror used near normal incidence reflects the incoming radiation onto the 2 m grating; this combination provides a horizontal exit beam, and enables the experiment to be located three meters from the orbit tangent point. With magnesium fluoride coated aluminum optics a flux of 2×10″ photons/s·Å at 1200 Å is observed with a 10 mA circulating current. A flux of 5×10 10 photons/sdÅ at 600 Å is observed with an osmium coated grating and a 10 mA circulating current. Sample spectra of the angle-resolved photoelectron spectrum of CO are presented.

Threshold photoelectron spectrum of CO by electron attachment (TPSA)

The threshold photoelectron spectrum of CO is reported in the photon energy range from 14.0 eV (photoionization threshold) to 21 eV. The technique used is threshold photoelectron spectroscopy by electron attachment (TPSA). Vibrational levels of the X 2Σ + state are observed up to high quantum numbers (ν′⋍ 12) and their population is found to be enhanced by resonant autoionization. Levels in the A 2Π and B 2Σ + states are also observed. Here, the measured vibrational populations more closely follow Franck—Condon intensities, so that for these states direct photoionization is more important. Qualitative molecular-orbital arguments are given to make plausible the enhancements observed in CO + and in previous measurements on N 2 +.

Ab initiopotential energy curves for the CO+ion and a study of the photoelectron spectra of CO

The potential energy curves for the low-lying electronic states of CO+ are calculated by using the ab initio full valence configuration interaction method with minimal STOs. Calculated spectroscopic parameters are given for twenty five bound states, and the compared with the experimental values for four observed bound states. The band systems, observed in the 22 eV and 27 eV region of He II photoelectron spectra of CO, are analysed by using calculated potential energy curves and spectral intensities. New assignment for the fourth band system at 22 eV ∼ 23 eV is proposed.

The chemisorption of CO on Cu(100) studied with angle resolved photoelectron spectroscopy

Using angle resolved UV photoelectron spectroscopy, coupled with the continuum of polarized light available with synchrotron radiation, we make an interpretation of the photoelectron spectrum of CO adsorbed on Cu(100). We point out that the bonding of CO on Cu as observed by photoemission is considerably different from the bonding of CO on Ni. These differences do not seem to be caused by bonding orientation differences, however, as the CO molecular axis is found to be very close to the surface normal, as was the case for CO on Ni(100). No evidence is found for a second phase of CO on Cu(100).

Formation and predissociation of CO+2(? 2Σ+g)

The discrepancy between photoionization mass spectrometry and photoelectron spectroscopy in the CO+/O+ ratio from CO2 at 584 Å is resolved by new measurements. New features in the photoelectron spectrum of CO+2(? 2Σ+g) lead to a new vibrational analysis, with vibration frequencies close to those of CO2(?1 Σ+g). The observations are discussed in terms of a perturbation of the ? 2Σ+g state by the ionization continuum of either the ? 2Πg state or the 4Πu state of CO+2.

Origin of satellite structure in the valence x-ray photoelectron spectrum of CO: A theoretical study

The satellite structure in the valence shell x-ray photoelectron spectrum (XPS) of CO is studied. The configuration interaction method is used to construct correlated many-electron wave functions for the different final states of C${\mathrm{O}}^{+}$. It is found that (1) the conventional shake-up model cannot explain the satellite structure; (2) a considerable amount of intensity is lost from the main, single-hole, $^{2}\ensuremath{\Sigma}^{+}$ states ($3{\ensuremath{\sigma}}^{\ensuremath{-}1}$, $4{\ensuremath{\sigma}}^{\ensuremath{-}1}$, and $5{\ensuremath{\sigma}}^{\ensuremath{-}1}$) due to electron correlation; and (3) the $3{\ensuremath{\sigma}}^{\ensuremath{-}1}$ peak satellites are at lower, rather than higher, binding energy than the main peak. Franck-Condon broadening is estimated and shown to be a major cause of the large width of the observed structures on the high-binding-energy side of the $4{\ensuremath{\sigma}}^{\ensuremath{-}1}$ peak. Our conclusions are supported by the results of other electron spectroscopies in addition to XPS.

The effect of the next nearest neighbor ion on the X-ray photoelectron spectra of 2p levels for Co2+, Ni2+ and Cu2+ in MgO

Abstract The X-ray photoelectron spectra of Co, Ni and Cu 2p levels for samples of MxMg1-xO (M = Co, Ni, Cu), CoO, NiO and CuO were compared. The binding energies of metal 2p 3 2 levels did not change with their concentration. The shake-up satellite main peak intensity ratios and FWHM of metal 2p levels for Co2+ and Cu2+ in MgO were smaller than those for CoO and CuO. The Ni 2p 3 2 spectrum for Ni2+ in MgO had no shoulder, unlike NiO. Results indicate that next nearest neighbor ions (metal ions) may influence the final states after photoelectron ejection.

X-ray photoelectron spectra of oxygen in oxides of Co, Ni, Fe and Zn

X-ray photoelectron spectra of Co-, Ni-, Fe- and Zn-oxides obtained by oxidation of metal films, as well as in powder form, were investigated. Two O (1

On the interpretation of the photoelectron spectrum of CO chemisorbed on Ni

A LCAO-SCF calculation on the NiCO molecule is reported. In addition to the ionization potentials the vibrational structure due to ionization is calculated. The computed ionization potentials are compared with those of recent semiempirical calculations on the CO — Ni system and with the photoelectron spectra of CO chemisorbed on nickel surfaces. We produce further evidence that the first peak in the photoelectron spectrum relates to the 5σ and 1π orbitals of CO and that the peak at higher ionization energy represents the 4σ orbital.

Valence and core-level photoelectron spectra of CO adsorbed on transition metal surfaces

Valence and core-level photoelectron spectra of CO adsorbed on transition metal surfaces

Photoelectron Spectrum and Rydberg Transitions of CO

A He II (304 Å) photoelectron spectrum of CO is presented and a new interpretation of the Rydberg series going to the higher excited states of CO+ is discussed. This work supports earlier assignments of these excited states.

CNDO model and interpretation of the photoelectron spectrum of CO chemisorbed on Ni

CNDO calculations for CO chemisorbed on a cluster of 10 Ni atoms produce a pattern of valence orbital energy levels that agrees well with the experimental photoelectron spectrum of CO adsorbed on Ni; thus allowing the experimental energies to be assigned to specific orbitals. The bonding of the carbon atom to the Ni atom largely involves nickel s and p orbitals, with little contribution from the d orbitals.

The absorption spectrum of carbon monoxide near 550 Å

Structure in the photoionization continuum of molecular carbon monoxide has been observed in the 530-620 A region, using the NBS 180 MeV electron synchrotron as a background source. An attempt has been made to analyse this complex, diffuse structure in terms of two-electron excitations. Recent photo-electron spectra of CO obtained with a He II 304 A line source have been used to help interpret the absorption spectrum.

Fluorescence excitation and photoelectron spectra of CO2induced by vacuum ultraviolet radiation between 185 and 716 Angstroms

Absolute yields are given for the production of fluorescent radiation from the A²Πu and B²Σu+ states of CO2+ caused by the photoionization of CO2 at wavelengths between 185 and 716 A. It is proposed that the initial population of the B state is perturbed by the proximity of the A state, and that the effect leads to the wide discrepancies found between the techniques of photoelectron spectroscopy and direct fluorescent measurements. In addition, the photoelectron spectrum at 304 A shows the appearance of the ²Σu and ²Σg states at 37 and 38.4 ev and the appearance of a very weak state at 25.7 ev.

Angular distribution of the photoelectron spectrum of CO 2, COS, CS 2, N 2O, H 2O, and H 2S

The photoelectron spectra of the triatomic molecules CO 2, COS, CS 2, N 2O, H 2O, and H 2S have been measured as a function of the angle θ between the direction of the incoming photon and outgoing photoelectron. The photoelectron spectra have been measured with a double-focusing electrostatic electron spectrometer to which has been attached a chamber containing a gas discharge lamp that can be freely rotated. (The photon source used was the 21.22 eV He I resonance line). From the dependence of intensity as a function of θ the angular parameter β was determined for each ionization band observed in the photoelectron spectra. A correlation was noted between the values of β and the molecular orbitals relative to the contributions of oxygen and sulfur atomic orbitals. Individual β values were also obtained for most of the vibrational bands seen in the photoelectron spectra. In most cases the vibrational structure showed little or no change in the angular parameter for a given electronic state. In certain cases, however, such as the fourth ionization band in CS 2, CO 2, and COS, rather sizeable changes in β were observed for the different vibrational bands.