Dissociative recombination of $\mathrm{H}{\mathrm{F}}^{+}$

The direct mechanism of dissociative recombination of $\mathrm{H}{\mathrm{F}}^{+}$ is studied using both time-dependent and time-independent methods, where the dynamics on 30 resonant states is explored. The relevant electronic states are calculated ab initio by combining electron scattering calculations with multireference configuration interaction structure calculations. For collision energies between 0.04 and $10\mathrm{eV}$, we obtain qualitative agreement with experiment. At $1.9\mathrm{eV}$ there is a sharp threshold in both the experimental and theoretical cross sections that can be explained by the opening of new asymptotic limits. The measured cross section below $0.04\mathrm{eV}$ is not reproduced due to the neglect of the electronic couplings between the neutral states. We examine the validity of the local approximation for treating autoionization from the resonant states included in this study.

Figure 1

The eigenphase sum from a scattering calculation of ${}^3\Pi$ symmetry at $R=1.9a_0$.

Figure 2

(Color online) Diabatic states for HF of (a) ${}^1\Sigma ^{+}$ and (b) ${}^3\Sigma ^{+}$ symmetries. Also the ground state $X{}^2\Sigma ^{+}$ of $\mathrm{H}{\mathrm{F}}^{+}$ is shown. The notation of the asymptotic energy limits for the resonant states follows the numbering in Table .

Figure 3

(Color online) Diabatic states for HF of (a) ${}^1\Pi$ and (b) ${}^3\Pi$ symmetries.

Figure 4

(Color online) Diabatic states for HF of (a) ${}^1\Delta$ and (b) ${}^3\Delta$ symmetries.

Figure 5

The gound vibrational wave function of $\mathrm{H}{\mathrm{F}}^{+}$.

Figure 6

(Color online) The autoionization widths for the four lowest (a) singlet and (b) triplet resonant states.

Figure 7

(Color online) Contribution to the cross section from the (a) $2{}^1\Sigma ^{+}$ and (b) $2{}^3\Sigma ^{+}$ resonant states, calculated using the local, time-dependent (wave packet) method and the time-independent local, and nonlocal methods.

Figure 8

Calculated total cross section using the local time-independent method. The experimental cross sections for DR and ion-pair formation measured at CRYRING are included for comparison [12]. The vertical lines correspond to the energies where the different asymptotic limits open up.

Figure 9

(Color online) Contributions from the lowest resonant states to the cross section. Included in the figure are also the experimental cross sections for DR and ion-pair formation. (a) Contributions from singlet states. (b) Contributions from triplet states.

Figure 10

(Color online) Contributions from the intermediate resonant states to the total cross section. Included is also the experimental cross section for DR.

Figure 11

(Color online) Contributions from the highest resonant states to the total cross section. Included is also the experimental cross section for DR.