Dyson orbitals for ionization from the ground and electronically excited states within equation-of-motion coupled-cluster formalism: Theory, implementation, and examples

Experimental and theoretical results for molecular-frame photoemission are presented for inner-valence shell photoionization of the CO molecule induced by linearly and circularly polarized light. The experimental recoil frame photoelectron angular distributions (RFPADs) obtained from dissociative photoionization measurements where the velocities of the ionic fragment and photoelectron were detected in coincidence, are compared to RFPADs computed using the multichannel Schwinger configuration interaction method. The formalism for including a finite lifetime of the predissociative ion state is presented for the case of general elliptically polarized light, to obtain the RFPAD rather than the molecular frame photoelectron angular distribution (MFPAD), which would be obtained with the assumption of instantaneous dissociation. We have considered photoionization of CO for the photon energies of 26.0 eV, 29.5 eV, and 32.5 eV. A comparison of experimental and theoretical RFPADs allows us to identify the ionic states detected in the experimental studies. In addition to previously identified states, we found evidence for the 2 (2)Δ state with an ionization potential of 25.3 eV and (2)Σ(+) states with ionization potentials near 32.5 eV. A comparison of the experimental and theoretical RFPADs permits us to estimate predissociative lifetimes of 0.25-1 ps for some of the ion states. Consideration of the MFPADs of a series of (2)Π ion states indicates the importance of inter-channel coupling at low photoelectron kinetic energy and the limitations of a single-channel analysis based on the corresponding Dyson orbitals.

Section: Photoionization Into Co + Ionic States In the 29-32 Ev Bimentioning

confidence: 99%

Valence and inner-valence shell dissociative photoionization of CO in the 26–33 eV range. II. Molecular-frame and recoil-frame photoelectron angular distributions

Lebech

Houver

Raşeev

et al. 2012

“…Using the ezDyson code, 44 the photoionisation matrix elements φ D I k |µ|ψ k are evaluated numerically on a grid and averaged isotropically over molecular orientations.…”

Section: Calculation Of Photoionization Cross-sectionsmentioning

confidence: 99%

Excited state non-adiabatic dynamics of pyrrole: A time-resolved photoelectron spectroscopy and quantum dynamics study

Neville

Schalk

et al. 2015

Coherent polyatomic dynamics studied by femtosecond time-resolved photoelectron spectroscopy: Dissociation of vibrationally excited C S 2 in the 6 s and 4 d Rydberg states J. Chem. Phys. 125, 174314 (2006) The dynamics of pyrrole excited at wavelengths in the range 242-217 nm are studied using a combination of time-resolved photoelectron spectroscopy and wavepacket propagations performed using the multi-configurational time-dependent Hartree method. Excitation close to the origin of pyrrole's electronic spectrum, at 242 and 236 nm, is found to result in an ultrafast decay of the system from the ionization window on a single timescale of less than 20 fs. This behaviour is explained fully by assuming the system to be excited to the A 2 (πσ * ) state, in accord with previous experimental and theoretical studies. Excitation at shorter wavelengths has previously been assumed to result predominantly in population of the bright A 1 (ππ * ) and B 2 (ππ * ) states. We here present time-resolved photoelectron spectra at a pump wavelength of 217 nm alongside detailed quantum dynamics calculations that, together with a recent reinterpretation of pyrrole's electronic spectrum [S. P. Neville and G. A. Worth, J. Chem. Phys. 140, 034317 (2014)], suggest that population of the B 1 (πσ * ) state (hitherto assumed to be optically dark) may occur directly when pyrrole is excited at energies in the near UV part of its electronic spectrum. The B 1 (πσ * ) state is found to decay on a timescale of less than 20 fs by both N-H dissociation and internal conversion to the A 2 (πσ * ) state. C 2015 AIP Publishing LLC. [http://dx

“…The relationship between the symmetries of the initial (bound) and final (continuum) states is defined by the transition-dipole selection rules. 7,14 Solid theoretical foundations have been developed for understanding the resulting angular distributions for the cases of atomic and small molecular anions, 8,[15][16][17][18][19] but it is less so for cluster anions. In general, PADs reflect the superposition of all allowed final states, as perhaps most apparent in atomic anion photodetachment.…”

Section: Introductionmentioning

confidence: 99%

Solvation effects on angular distributions in H−(NH3)n and NH2−(NH3)n photodetachment: Role of solute electronic structure

Grumbling

Sanov

2011

We report 355 and 532 nm photoelectron imaging results for H(-)(NH(3))(n) and NH(2)(-)(NH(3))(n), n = 0-5. The photoelectron spectra are consistent with the electrostatic picture of a charged solute (H(-) or NH(2)(-)) solvated by n ammonia molecules. For a given number of solvent molecules, the NH(2)(-) core anion is stabilized more strongly than H(-), yet the photoelectron angular distributions for solvated H(-) deviate more strongly from the unsolvated limit than those for solvated NH(2)(-). Hence, we conclude that solvation effects on photoelectron angular distributions are dependent on the electronic structure of the anion, i.e., the type of the initial orbital of the photodetached electron, rather than merely the strength of solvation interactions. We also find evidence of photofragmentation and autodetachment of NH(2)(-)(NH(3))(2-5), as well as autodetachment of H(-)(NH(3))(5), upon 532 nm excitation of these species.