Figure 1

(a) Total-ion-yield spectra for photon energies scanned over the carbon and oxygen $K$ edges. (b) Ion fragment mass spectra of furan recorded for various photon energies. The intensities are normalized to an arbitrary value of the intensity of the ${\text{C}}^{+}$ ions (mass 12). The fragments ${\text{C}}_3{{\text{H}}_y}^{+}$, ${\text{C}}_2{{\text{OH}}_y}^{+}$, ${\text{C}}_4{{\text{H}}_y}^{+}$, and ${\text{C}}_3{{\text{OH}}_y}^{+}$ are labeled as (i)–(iv).Reuse & Permissions

Figure 2

Probabilities for the emission of fragment ion pars after ionization by 548 eV photons. The first detected ion is marked above the arrow, while the second detected ion is represented using a color and pattern scheme. The probabilities for the detection of various ions are shown in the inset (noncoincidence data).Reuse & Permissions

Figure 3

Flow chart showing possible fragmentation pathways. The ions produced are written in bold.Reuse & Permissions

Figure 4

Magnified parts of the two-dimensional covariance (PIPICO) map. Selected ion pairs are labeled. This correlation map was recorded for photon energy 535.2 eV. Almost identical maps are obtained for other photon energies.Reuse & Permissions

Figure 5

(a) Newton diagrams for ${\text{H}}^{+}-X^{+}$ fragmentation channels (535.2 eV). The corresponding ions ($X^{+}$) are labeled. Newton diagrams in the lowest row are plotted for specific energy intervals of ${\text{H}}^{+}$ ions (labeled). The color scale is normalized to 100%. The total number of detected events varies from 73 000 for ${\text{H}}^{+}{\text{-C}}^{+}$ pairs (350 peak value) to 3500 (28 in the peak) for ${\text{H}}^{+}\text{-C}{{\text{H}}_2}^{+}$ pairs. The relative ratio of intensities is depicted in Fig. 2. (b) Polar plot showing the angular distribution of different fragments with respect to the ${\text{H}}^{+}$ ion.Reuse & Permissions

Figure 6

Kinetic energy distribution of photofragments for ${\text{H}}^{+}{\text{-C}}^{+}$ and ${\text{H}}^{+}\text{-C}{{\text{H}}_2}^{+}$ channels. The data are arbitrarily scaled for the purpose of comparison. The photon energy is 535.2 eV.Reuse & Permissions

Figure 7

Kinetic energy distribution of protons from ${\text{H}}^{+}{\text{-C}}_x{{\text{H}}_y}^{+}$, ${\text{H}}^{+}{\text{-O}}^{+},\hspace{0.5em}{\text{H}}^{+}{\text{-CO}}^{+}$, and ${\text{H}}^{+}{\text{-COH}}^{+}$ channels. The second fragment is noted in parentheses. Photon energy was 535.2 eV.Reuse & Permissions

Figure 8

Newton diagrams (a), polar plot (b), and kinetic energy distributions (c) for selected ${\text{C}}^{+}-X^{+}$ channels ($X^{+}\equiv {\text{CH}}^{+},{\text{C}}_2{\text{H}}^{+}$, etc., as labeled). Photon energy was 535.2 eV. The color scale is normalized to 100. The relative intensity can be estimated from Fig. 2.Reuse & Permissions

Figure 9

Sum of momenta of remaining fragments $p_r=-p_1-p_2$ plotted relative to the reference ion (represented by the arrow). The fragmentation channel is labeled in parentheses. The color scale is arbitrarily normalized to 100. The relative intensity can be estimated from Fig. 2.Reuse & Permissions

Figure 10

Results of the CE model for different fragmentation pathways leading to ${\text{H}}^{+}{\text{-C}}^{+}$ ions. Concerted processes and secondary decay are plotted in the left and the right parts of the polar plot for various configurations of the molecular ion, while the results for deferred charge separation are plotted using dotted lines.Reuse & Permissions