Carbon 1s photoelectron spectra of methane are measured over a photon energy range between 480 eV and 1200 eV. Additional components appear the individual symmetric stretching vibrational attributed to excitations asymmetric bending vibrations due recoil high-energy emission. This effect is evidence for violation Franck-Condon principle which states that neither positions nor momenta nuclei change during ionization event.

The two-dimensional yield spectrum of fluorescence radiation from excited O atoms produced in the neutral photodissociation ${\mathrm{O}}_{2}$ is measured as a function both excitation photon wavelength 50-62 nm (24.8-20 eV energy) and 80-140 nm. State-to-state dissociation pathway Rydberg states converging onto ${{\mathrm{O}}_{2}}^{+}(c^{4}\ensuremath{\Sigma}_{u}^{\ensuremath{-}})$, ${v}^{\ensuremath{'}}=1$ into $\mathrm{O}(ns^{3}S)+\mathrm{O}(^{1}D)$ limit revealed, where principal quantum...

Absolute total cross sections for electron scattering from Ar and Xe at energies ranging 7 meV to 20 eV were obtained with the experimental technique employing threshold-photoelectron source. The measured are in good agreement those by other groups down 100 meV, above which several works have been reported. Scattering lengths Ar, Kr, determined present our recent results Kr using modified effective range theory. values of length analysis differ previous swarm experiments beam experiments....

We present absolute measurements of differential elastic electron scattering cross sections from benzene (C6H6) and hexafluorobenzene (C6F6). The have been performed in our two laboratories on different crossed-beam apparatuses for angles between 10° 130°: C6H6 at the Australian National University energy range 1.1 to 40 eV, C6F6 Sophia 1.5 100 eV. both molecules, which are characterized by strong forward-angle large-angle oscillations, favourably compared with recent theoretical calculations.

We have measured absolute elastic scattering and vibrational excitation cross sections for electron impact on ethylene. The experimental data been obtained two different crossed-beam spectrometers they cover the energy range from 1 to 100 eV angles between 10° 130°. Both differential (in angle) energy-dependent measured. also analysed using a molecular phase shift analysis technique in order derive integral momentum transfer sections. Comparison is made with earlier data, where available,...

We have carried out a coincidence experiment between energy-resolved resonant Auger electrons and mass-resolved ions on ${\mathrm{CH}}_{3}\mathrm{F}$ molecules following F $1s$ C excitation to the lowest unoccupied C--F antibonding molecular orbital ${\ensuremath{\sigma}}_{\mathrm{CF}}^{*}$. found strong enhancement of ${\mathrm{F}}^{+}$ or ${\mathrm{CH}}^{+}$ ion production in with $KVV$ spectator electrons, respectively, wide binding energy range 28--36 eV. This site-selective is...

Fragmentation of the SF6 molecule upon F 1s excitation has been studied by resonant photoemission. The atomiclike Auger line exhibits characteristic Doppler profile that depends on direction photoelectron momentum relative to polarization vector radiation as well photon energy. measured profiles are analyzed model simulation takes account anisotropy emission in molecular frame. extracted from data decreases with an increase F-SF5 internuclear distance.

The resonant Auger spectrum from the decay of F 1s-excited CF4 is measured. Several lines exhibit a nondispersive kinetic energy as exciting photon tuned through resonance region. 1s(-1) atomiclike line split into two components due to emission electrons by fragment in motion, when electron observed along polarization vector light. This Doppler splitting direct evidence that core excitation leads T(d)-->C(3v) symmetry lowering, elongation specific C-F bond preferentially aligned incident photon.

We have carried out angle-resolved measurement for the C $1s$ photoelectron shakeup satellites of gaseous CO molecules, at unprecedented energy resolution, and resolved vibrational structures one $^{2}\ensuremath{\Sigma}^{+}$ two $^{2}\ensuremath{\Pi}$ bands. The present ab initio calculations potential curves these satellite states relevant Franck-Condon analysis well reproduce bands confirm assignments.

The photon-ion merged beam technique has been used to measure the ionization cross sections of I-, Cs+, Ba+ and Ba2+ ions in energy region from 40 185 eV, which is dominated by photoexcitation 4d shell (the experimental data are available at http://www.ifa.au.dk/amo/atomphys/atomphys.htm). Within accuracy, total oscillator strengths for these I+, I2+, Xe+ Xe2+ ions, that were recently studied some present authors, identical, with contribution → np or nf resonances becoming more important...

Ultrafast dissociation of the SF6 molecule following F 1s → a*1g excitation has been studied by coincident measurement kinetic energy resonantly emitted electron and momentum fragment ion. The nuclear motion takes place on same time scale as Auger decay, leading to atomic-like (1s)-Auger lines in spectrum. De-tuning from resonance changes ratio two scales involved. We measured shift line parameters that describe corresponding ionic fragmentation dynamics a function detuning energy. Our data...

Theoretical and experimental study of vibrationally resolved partial photoionization cross sections angular asymmetry parameter β for the 1σg 1σu shells N2 molecule in region σ* shape resonance is reported. The measurements were made at synchrotron radiation facility SPring-8 Japan. calculations random phase approximation have been performed using relaxed core Hartree–Fock wavefunctions with fractional charge ion equal to 0.7. With its help, role interchannel coupling between closely spaced...

The photoelectron shake-up satellite spectra that accompany the C1s and O1s main lines of carbon monoxide have been studied by a combination high-resolution x-ray spectroscopy accurate ab initio calculations. symmetry-adapted cluster-expansion configuration-interaction general-R method satisfactorily reproduces over wide energy region, quantitative assignments are proposed for 16 12 bands spectra, respectively. Satellite peaks above π−1π* transitions mainly assigned to Rydberg excitations...

Total cross sections for electron ${(e}^{\ensuremath{-}})$ and positron ${(e}^{+})$ scattering from ${\mathrm{C}}_{3}{\mathrm{H}}_{8}$ ${\mathrm{C}}_{3}{\mathrm{F}}_{8}$ have been measured 0.8 to 600 eV 0.7 eV, respectively. We also investigated differential elastic by impact 2.0 200 compared them with the present theoretical results. For ${e}^{\ensuremath{-}}$ ${\mathrm{C}}_{3}{\mathrm{H}}_{8},$ are found be larger a factor of 2 than those ${e}^{+}$ below 20--30 eV. They show large peak at...

O $1s$ single-hole ionization cross sections of CO have been measured for ${v}^{\ensuremath{'}}=0\ensuremath{-}2.$ The ${1s}^{\ensuremath{-}1}{\ensuremath{\sigma}}^{*}$ shape resonance moves up in energy with an increase ${v}^{\ensuremath{'}},$ opposite to the C observed previously. Theoretical calculations beyond fixed-nuclei approximation reproduce these experimental results. relationship between ${v}^{\ensuremath{'}}$-dependent characteristic internuclear distance residual ion and is discussed.

We have studied angular correlations between resonant Auger electrons and successive second-step emitted in a cascade decay after photoexcitation of resonances 3d5/2−1 5p Kr 4d5/2−1 6p Xe. Two spectrometers were used for the angle-resolved detection two coincidence. Angular several pairs strong lines been measured both atoms. The experimental results are compared with multiconfiguration Dirac–Fock calculations which include electron initial, intermediate final states cascade. In general,...

Absolute differential cross sections (DCSs) for elastic and vibrationally inelastic scattering of electrons from ${\mathrm{C}}_{3}{\mathrm{H}}_{4}$ isomers (allene propyne) have been determined by a crossed-beam experiment in the energy range 1.5--100 eV over angles between 15\ifmmode^\circ\else\textdegree\fi{}--130\ifmmode^\circ\else\textdegree\fi{}. The relative flow method was applied to normalize these sections, using helium as standard. Clear evidence strong isomer effect has observed...

We present measured and calculated differential cross sections, as well integral for elastic electron collisions with ${\mathrm{CH}}_{3}\mathrm{F},$ ${\mathrm{CH}}_{2}{\mathrm{F}}_{2},$ ${\mathrm{CHF}}_{3},$ ${\mathrm{CF}}_{4}.$ The sections were obtained the Schwinger multichannel method, a Born-closure procedure was used to improve polar systems. Polarization effects found be relevant even systems moderately large permanent dipole moments, such ${\mathrm{CH}}_{3}\mathrm{F}$...

We use recapture of near-threshold photoelectrons by postcollision interaction with Auger electrons as an effective method for population the high-Rydberg states subvalence ionized Ne ions. The subsequent intermultiplet transitions are detected high-resolution electron spectrometry. series $2{p}^{4}(^{1}D)np\phantom{\rule{0.3em}{0ex}}^{2}D,^{2}F\ensuremath{\rightarrow}2{p}^{4}\phantom{\rule{0.3em}{0ex}}^{3}P$ up to $n=20$ observed and identified help multiconfiguration Dirac--Fock ab initio...

Methane and deuteromethane molecules were core ionized using synchrotron radiation, the ionic fragments from molecular dissociation detected in coincidence with Auger electrons. The electron–ion spectra are analysed terms of partial ion yields kinetic energy distributions, both as functions electron energy. dependence fragmentation patterns on electronic character final states well excess available for dissociating molecule is studied. analysis reveals marked differences 2a−21 2a−111t−12...

We have measured the vibrationally resolved partial cross sections ${\ensuremath{\sigma}}_{({v}_{1}^{\ensuremath{'}},{v}_{2}^{\ensuremath{'}},{v}_{3}^{\ensuremath{'}})}$ and asymmetry parameters ${\ensuremath{\beta}}_{({v}_{1}^{\ensuremath{'}},{v}_{2}^{\ensuremath{'}},{v}_{3}^{\ensuremath{'}})}$ for ${\mathrm{N}}_{\mathrm{c}}$ ${\mathrm{N}}_{\mathrm{t}}$ $K$-shell photoionization of ${\mathrm{N}}_{2}\mathrm{O}$ molecule in ${\ensuremath{\sigma}}^{*}$ shape resonance region above ionization...

We report on an experimental and theoretical investigation of x-ray absorption resonant Auger electron spectra gas phase O2 recorded in the vicinity O 1s→σ* excitation region. Our shows that core takes place a region with multiple crossings potential energy curves excited states. find complete breakdown diabatic picture for this part spectrum, which allows us to assign hitherto unexplained fine structure spectral The data reveal extended vibrational progression, outermost singly ionized XΠg2...

Absolute total cross sections for electron scattering from He and Ne are obtained in the energy range 20 eV down to below 10 meV with a very narrow width of 6--8 using threshold-photoelectron source. Total present study generally agree well those previous experiments both above 100 meV, where several experimental works have been reported. Comparison theoretical which regarded as ``standard'' shows good agreement even at low energies confirms validity sections. The lengths also determined...