O Furuhashi

Double charge transfer spectroscopy for N22+ and CO2+ at vibrational resolution

Abstract Doubly charged molecular ions (dications) of N 2 and CO have been studied using a double charge transfer (DCT) spectrometer capable of resolving vibrational levels. The vibrational structures of low-lying singlet states are observed in the translational energy spectra of H − ions produced by double electron capture collisions of H + projectiles. The observed spectra are well reproduced using the theoretical Franck–Condon (FC) profiles calculated from the best available ab initio potential curves. This suggests that the DCT process obeys the FC principle, i.e., the vertical transition from a neutral molecule to the corresponding dication.

Double charge transfer spectroscopy of acetylene dication C2H22+ at vibrational resolution

Abstract We have observed a vibrational progression of C2H22+ with double charge transfer (DCT) spectroscopy. From an exploratory calculation, the progression is assigned to the symmetric C–C stretching mode of the lowest singlet 1 Δ g state with linear geometry. The observed structure is well reproduced with the theoretical Franck–Condon (FC) factors obtained from the potential curves of the 1 Δ g and first-excited 1 Σ g + states along the normal C–C stretching coordinate. Multi-reference CI calculations reveal a predominant contribution of the 1 Δ g state. These results suggest that the DCT process can probe dicationic states of polyatomic molecules like acetylene with resort to the FC principle.

Angular distribution of metastable fragments of produced by electron impact dissociative excitation of

The angular distribution of metastable fragments produced by electron impact dissociative excitation of has been measured at two impact energies (15 and 40 eV) with time-of-flight (TOF) spectroscopy. A simple TOF system which can be utilized for such studies is introduced. The parent molecular symmetry before dissociation was determined from the angular distribution, using this system. The angular distribution indicates that the process is direct dissociation, predominantly from a weakly bound -state.

Abel Inversion Scheme for Marked Improvement of a Reflectron Time-of-Flight Mass Spectrometer

This letter describes a simple Abel inversion scheme for marked improvement of a reflectron time-of-flight (TOF) mass spectrometer having a reflecting electric potential U(X) along its central axis X. To maximize the resolving power, the inverse function X(U) was determined using the Abel inversion of the most-desirable TOF τ(E), which is a function of the total energy E. Based on the linear nature of the Abel transform, we could derive an additional condition necessary for the electrostatic realization of X(U). Our numerical results demonstrated the definite superiority of this approach compared with the conventional energy-focusing method.

Polarization of electron impact radiation 7 3S rightarrow 6 3PJ from a Hg atom

Polarization of the 7 3S 6 3PJ radiation from the Hg atom was observed under electron impact with an energy a little above the 6 1S 7 3S threshold excitation energy. The observing direction was perpendicular to both the incident electron beam and the atomic beam. All of the triplet radiation (J = 0, 1 and 2) was slightly polarized. The observed degree of fractional polarization was -3.07, 1.98 and -0.33%, corresponding to J = 0, 1 and 2 spectra in the final 3PJ states of the Hg atom, respectively. These values could be explained by assuming unequal populations in the sublevels Ms = 0 and ±1 of the 7 3S states, deviating from an equal mean value of (1/3) for each sublevel. The deviation value of the fractional population for the sublevel Ms = 0 was 0.348±0.004.

Polarization of electron impact radiation from Zn and Cd atoms ( n = 4 for Zn and 5 for Cd)

Polarization of the radiation from Zn and Cd atoms (n = 4 for Zn and 5 for Cd, respectively) was observed after electron impact with energy slightly above the threshold excitation energy. The observing direction was perpendicular to both the incident electron beam and the atomic beam. All of the triplet radiation (J = 0, 1 and 2) was slightly polarized. The observed fractional polarization degrees were and corresponding to J = 0, 1 and 2 spectra in the final states of the Zn atom and , 4.3 and for the Cd atom. These values could be explained by assuming populations in the sublevels and of the states deviating from an equal mean value of for each sublevel. It is interesting and reasonable that the deviations determined independently for different states coincided with each other quite well. The deviated values of fractional population for the sublevel were 0.36 for Zn and 0.37 for Cd, respectively.