Isomer-specific photofragmentation of CH at the carbon K-edge.

Individual fingerprints of different isomers of CH cations have been identified by studying photoionization, photoexcitation, and photofragmentation of CH near the carbon K-edge. The experiment was performed employing the photon-ion merged-beams technique at the photon-ion spectrometer at PETRA III (PIPE). This technique is a variant of near-edge X-ray absorption fine-structure spectroscopy, which is particularly sensitive to the 1s → π* excitation.

An integrated ion trap for the photon-ion spectrometer at PETRA III.

We have added a multipole ion trap to the existing photon-ion spectrometer at PETRA III (PIPE). Its hybrid structure combines a ring-electrode trap with a segmented 16-pole trap. The interaction of gases and ions with extreme ultraviolet radiation from the beamline P04 is planned to be investigated with the newly installed multipole trap.

Vibrationally Resolved Inner-Shell Photoexcitation of the Molecular Anion C.

Carbon 1s core-hole excitation of the molecular anion C has been experimentally studied at high resolution by employing the photon-ion merged-beams technique at a synchrotron light source. The experimental cross section for photo-double-detachment shows a pronounced vibrational structure associated with and core excitations of the C ground level and first excited level, respectively. A detailed Franck-Condon analysis reveals a strong contraction of the C molecular anion by 0.

X-Ray absorption spectroscopy of HO.

We report the X-ray absorption of isolated HO cations at the O 1s edge. The molecular ions were prepared in a flowing afterglow ion source which was designed for the production of small water clusters, protonated water clusters, and hydrated ions. Isolated HO cations have been analyzed for comparison.

Disentangling the Photodissociation Dynamics of the HF Molecular Radical via Kinetic-Energy-Release-Resolved F 1s Core Excitation and Ionization.

The F 1s core level photoionization of the ionic molecular radical HF has been studied using the photon-ion merged-beams technique at a synchrotron radiation source. Upon analyzing kinetic energy release (KER) dependent photoion yield spectra, complex ultrafast dissociation dynamics of the F 1s core hole excited σ* state can be revealed. By means of configuration-interaction electronic structure calculations of the excited molecular potential energy curves, this complex process can be attributed to a spin-dependent dissociation of the excited σ* biradical state.