Controlling molecular orientation through radiative rotational transitions in strong static electric fields

The effects of a static, homogeneous, and strong electric field on the radiative and steric properties of the LiCs molecule in its ${}^1\Sigma ^{+}$ electronic ground state are investigated. Combining discretization and basis-set methods, the rovibrational Schrödinger equation is solved and dipole transition rates are calculated. Spontaneous emission decay rates and radiative lifetimes of rovibrationally excited states have been studied extensively and particularly in the presence of the external homogeneous electric field. The intriguing possibility to control the alignment and orientation by applying a sufficiently strong field while switching between different configurations via absorption and emission processes is demonstrated.

Figure 1

Electronic potential energy curve (solid line) and electric dipole moment function (dashed line) of the electronic ground state of the LiCs molecule. Both quantities are given in atomic units.

Figure 2

Lifetimes (grid points) and transition probabilities (arrows) per unit time of vibrational ground states with $J⩽5$ and $M⩽5$, for zero field strength. The lifetimes are given in units of ${10}^5\mathrm{s}$, the transition rates in ${10}^{-5}{\mathrm{s}}^{-1}$.

Figure 3

Same as in Fig. 2 but for $F={10}^{-5}\mathrm{a.u.}$ For each state, only the dominant decay channels are displayed. The lifetimes are given in units of ${10}^4\mathrm{s}$, the transition rates in ${10}^{-5}{\mathrm{s}}^{-1}$.

Figure 4

Same as in Fig. 2 but for $F={10}^{-4}\mathrm{a.u.}$ For each state, only the dominant decay channels are displayed. The lifetimes are given in units of ${10}^3\mathrm{s}$, the transition rates in ${10}^{-4}{\mathrm{s}}^{-1}$.

Figure 5

Transition probabilities and lifetimes of the fully angular momentum polarized states with $J⩽5$ and $v=10$ for $F=0$. For each state, only the dominant decay channels are displayed. The actual transitions correspond to the labels summarized in Table .

Figure 6

Same as in Fig. 5 but for $F={10}^{-5}\mathrm{a.u.}$

Figure 7

Same as in Fig. 5 but for $F={10}^{-4}\mathrm{a.u.}$

Figure 8

(Color online) Probability densities for the decay cascade starting at $J=M=5$, for the vibrational ground state and the field strength $F={10}^{-4}\mathrm{a.u.}$ Inset: The course of the corresponding expectation value $⟨\cos \theta ⟩\pm \Delta \cos \theta$.

Figure 9

(Color online) Probability densities for the decay cascade starting at $J=M=5$, for the vibrational ground state and the field strength $F=0$.

Figure 10

(Color online) Same as in Fig. 8 but for a cascade starting at $J=5$, $M=2$.