From Ground to Excited State: Revealing Bond Polarity Change via KV Spectroscopy and Brillouin Inverse Theorem (BIT).

We report carbon and fluorine KV double core hole (DCH) spectra of CHF, recorded by single-photon hard X-ray photoelectron spectroscopy. A striking inversion in intensity between the and K7(3) resonances reflects a polarity switch in bonding character depending on the K-shell vacancy site. Within the Brillouin Inverse Theorem (BIT) framework, the transition strengths are shown to depend on the bielectronic integral (V = σ*, 3).

Revealing ligand deprotonation and speciation pathways in Cu(II)-glycine aqueous solutions liquid-jet X-ray photoelectron spectroscopy supported by calculations.

We present an integrated methodology combining photoemission spectroscopy, chemical speciation modeling, and calculations to investigate aqueous solutions of copper chloride salts mixed with glycine. This system is of interest due to the role of amino acid-metal interactions in biological and environmental contexts. Speciation simulations based on chemical equilibrium models reveal the formation of Cu-(glycine) and Cu-(glycine) complexes, with relative abundances that depend on initial ion concentrations.

Oxygen Vacancy Dynamics in Different Switching Modes of HfZrO.

HfO, one of the most common materials in resistive switching devices, can stabilize in a ferroelectric orthorhombic phase, enabling two nonvolatile polarization states via oxygen displacement in the unit cell. Under certain conditions, ferroelectric and resistive switching can coexist, independently addressable, within one device. This study employs spectroscopic analysis to elucidate the role of oxygen in both switching processes.

Symmetry Breaking around Aqueous Ammonia Revealed in Nitrogen K-edge X-ray Absorption.

Nitrogen K-edge X-ray absorption (XA) spectroscopy of aqueous ammonia reveals a splitting in the main-edge, which through theoretical modeling is shown to be related to symmetry breaking in hydrogen bonding. The XA main-edge of NH is formed by a pair of degenerate core-excitations into extended molecular orbitals. In aqueous solution, these form an antibonding mixture with orbitals of the surrounding water molecules.

Attosecond formation of charge-transfer-to-solvent states of aqueous ions probed using the core-hole-clock technique.

Charge transfer between molecules lies at the heart of many chemical processes. Here, we focus on the ultrafast electron dynamics associated with the formation of charge-transfer-to-solvent (CTTS) states following X-ray absorption in aqueous solutions of Na, Mg, and Al ions. To explore the formation of such states in the aqueous phase, liquid-jet photoemission spectroscopy is employed.