New Photoelectron–Valence Electron Interactions Evident in the Photoelectron Spectrum of Gd₂O^–

Abstract

Evidence of strong photoelectron–valence electron (PEVE) interactions has been observed in the anion photoelectron (PE) spectra of several lanthanide suboxide clusters, which are exceptionally complex from an electronic structure standpoint and are strongly correlated systems. The PE spectrum of Gd2O–, which should have relatively simple electronic structure because of its half-filled 4f subshell, exhibits numerous electronic transitions. The electron affinity determined from the spectrum is 0.26 eV. The intensities of transitions to excited states increase relative to the lower-energy states with lower photon energy, which is consistent with shakeup transitions driven by time-dependent electron–neutral interactions. A group of intense spectral features that lie between electron binding energies of 0.7 and 2.3 eV are assigned to transitions involving detachment of an electron from outer-valence σu and σg orbitals that have large Gd 6s contributions. The spectra show parallel transition manifolds in general, which is consistent with detachment from these orbitals. However, several distinct perpendicular transitions are observed adjacent to several of the vertical transitions. A possible explanation invoking interaction between the ejected electron and the high-spin neutral is proposed. Specifically, the angular momentum of electrons ejected from σu or σg orbitals, which is = 1, can switch to = 0, 2 with an associated change in the Ms of the remnant neutral, which is spin–orbit coupling between a free electron and the spin of a neutral.

Photoelectron imaging of PtI2− and its PtI− photodissociation product

“…[18][19][20] Jarrold and coworkers have recorded photoelectron spectra for some transition metal and lanthanide clusters, including NiO − and Gd2O − , at different laser polarisations relative to the detector, in order to gain some information about the PADs and characterise the spectroscopic transitions. 21,22 Here, we record the full PADs, using photoelectron imaging, in order to investigate the symmetry of the molecular orbitals of transition metal complexes. Moreover, for the case of platinum iodides, spin-orbit coupling and relativistic effects are likely to be large and these can have striking influences on the molecular orbitals of such complexes, which again the PADs may be sensitive to.…”

Electronic Structure of Heteronuclear Cerium-Platinum Clusters

“…These transitions have proven to be common from past studies on lanthanide oxides. 27,83,84,88,89,93 The spectral simulation based on the transition to the 1 N* state shows a vibrational progression in the Ce 2 -O stretch that is similar in appearance to band A in the experimental spectrum, as shown in Figure 6a. The inset in Figure 6a shows the appearance of the 1 N-2 A transition with the spectral origin shifted from 0.98 to 1.09 eV, to compare the experimental profile of band X to the simulated profile of this computation-based simulation.…”

“…78 oxide clusters with high spins, and it has been attributed to spin polarization of the singly occupied outervalence orbitals. 89 Figures 4 and 5 show the orbital occupancies of the lowest energy neutral and anion of Ce 2 OPt, respectively, found computationally, which serve to illustrate this effect. Focusing first on Figure 4, which shows only subtle spin polarization in the quintet neutral, the molecular orbitals can be broken into three categories: MOs predominantly of Ce parentage (6s, 4f, shown on the left portion of Figure 4), MOs predominantly of Pt parentage (6s, 5d, shown on the right portion of Figure 4), and MOs predominantly of O parentage (2p, bottom left of Figure 4).…”

Comparison of Linear Response Theory, Projected Initial Maximum Overlap Method, and Molecular Dynamics-Based Vibronic Spectra: The Case of Methylene Blue

“…As such, MOM-based simulations do not artificially impose symmetry or other constraints on the wave function (other than the inherent limitations of a single-determinant representation) or the geometry optimization. In recent years, MOM-based calculations have successfully been used to study valence excitation energies, excited-state geometries and vibrational frequencies, core-level excitations, and ionization energies. ,,,− , …”

“…In recent years, MOM-based calculations have successfully been used to study valence excitation energies, excited-state geometries and vibrational frequencies, core-level excitations, and ionization energies. 17,18,24,[30][31][32][33][34][35][36][37][38][39][40][41][42]67 Vibronic spectra can be computed with a variety of methods. [43][44][45][46]100 Perhaps the most popular method for larger molecules is to parametrize harmonic potentials by computing the Hessian and then using the frequencies and displacements from normal modes computed at the ground-and excited-state minima, which takes the form of a generalized Brownian oscillator model (GBOM).…”