We report an experimental study of the highly excited 3(1)Delta(g) and 4(1)Delta(g) electronic states of the Rb2 molecule. Rovibrational levels of the two electronic states were probed using the high-resolution optical-optical double resonance technique by exciting Rb-85(2) molecules from thermally populated levels of the X-1 Sigma(+)(g) ground state through intermediate levels of the B-1 Pi(u) electronic state. The (1)Delta(g) resonances induced by the probe laser were observed by detecting laser induced fluorescence from collisionally populated triplet states lying near the upper (1)Delta(g) states to the a(3)Sigma(+)(u) triplet ground state. The (1)Delta(g) character of the two electronic states was confirmed by showing that the probe transitions to these states abide by (1)Delta <-(1)Pi dipole selection rules and by observing that their lowest rotational level is J=2. A set of molecular constants and a Rydberg-Klein-Rees potential-energy curve were calculated from the observed term values for each electronic state and compared with ab initio predictions.

We have produced state selective molecular angular momentum orientation using dressed states created by a cw optical field. The experiment was carried out with Li2 molecules and a combination of left- and right-hand circularly polarized lasers. Our approach exploits the dependence of the Rabi frequency on the quantum number M , which makes it possible to achieve complete M-state selectivity and thus molecular angular momentum orientation relative to laboratory frame space-fixed axes. Using molecules in a 1 Sigma state, orientation of the rotational angular momentum, R , can be achieved by spectrally resolving the AutlerTownes split M components of the total angular momentum, J .

The simulation of the predissociation spectrum of the Na2 23Πg∼33Πg←b3Πu (v=14,J=14) transition, observed earlier with the Perturbation Facilitated Optical–Optical Double Resonance (PFOODR) experimental method, is done within the Optimizer project with our Split-operator computational package using Padé approximations for all functions involved in the model. This simulation reproduces the experimental spectrum satisfactory well. The parameters of the model functions involved in the simulations are determined and reported. A brief description of our computational methods and programs is presented.

We report an experimental study of the highly excited $3{\phantom{\rule{0.16em}{0ex}}}^{1}{\mathrm{\ensuremath{\Delta}}}_{g}$ and $4{\phantom{\rule{0.16em}{0ex}}}^{1}{\mathrm{\ensuremath{\Delta}}}_{g}$ electronic states of the ${\mathrm{Rb}}_{2}$ molecule. Rovibrational levels of the two electronic states were probed using the high-resolution optical-optical double resonance technique by exciting $^{85}{\mathrm{Rb}}_{2}$ molecules from thermally populated levels of the $X{\phantom{\rule{0.16em}{0ex}}}^{1}{\mathrm{\ensuremath{\Sigma}}}_{g}^{+}$ ground state through intermediate levels of the $B{\phantom{\rule{0.16em}{0ex}}}^{1}{\mathrm{\ensuremath{\Pi}}}_{u}$ electronic state. The $^{1}\mathrm{\ensuremath{\Delta}}_{g}$ resonances induced by the probe laser were observed by detecting laser induced fluorescence from collisionally populated triplet states lying near the upper $^{1}\mathrm{\ensuremath{\Delta}}_{g}$ states to the ${a\phantom{\rule{0.16em}{0ex}}}^{3}{\mathrm{\ensuremath{\Sigma}}}_{u}^{+}$ triplet ground state. The $^{1}\mathrm{\ensuremath{\Delta}}_{g}$ character of the two electronic states was confirmed by showing that the probe transitions to these states abide by ${}^{1}\mathrm{\ensuremath{\Delta}}\ensuremath{\leftarrow}{\phantom{\rule{0.16em}{0ex}}}^{1}\mathrm{\ensuremath{\Pi}}$ dipole selection rules and by observing that their lowest rotational level is $J=2$. A set of molecular constants and a Rydberg-Klein-Rees potential-energy curve were calculated from the observed term values for each electronic state and compared with ab initio predictions.

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This paper reports a high-resolution experimental study of the 3(3)Pi(g) and 4(3)Sigma(+)(g) electronic states of the Rb-85(2) dimer. In the experiment, rovibrational levels of the two electronic states were probed using the perturbation facilitated optical-optical double resonance technique by exciting Rb-85(2) molecules from thermally populated levels of the ground X-1 Sigma(+)(g) state through intermediate levels of the mixed A1 Sigma(+)(u) similar to b(3)Pi(u) electronic states. The resonances of the probe laser were observed by detecting the laser induced fluorescence from the target states to the a a(3)Sigma(+)(u) triplet ground state. In addition, to confirm the triplet character as well as the vibrational quantum number assignment of the states, for selected resonances the fluorescence to the a(3)Sigma(+)(u) state was resolved and bound-free spectra were recorded. From the observed term values for each state potential-energy curves were constructed using the Rydberg-Klein-Rees method.

This paper reports a high-resolution experimental study of the $3^{3}\mathrm{\ensuremath{\Pi}}_{g}$ and $4^{3}\mathrm{\ensuremath{\Sigma}}_{g}^{+}$ electronic states of the $^{85}\mathrm{Rb}_{2}$ dimer. In the experiment, rovibrational levels of the two electronic states were probed using the perturbation facilitated optical-optical double resonance technique by exciting $^{85}\mathrm{Rb}_{2}$ molecules from thermally populated levels of the ground $X^{1}\mathrm{\ensuremath{\Sigma}}_{g}^{+}$ state through intermediate levels of the mixed $A^{1}\mathrm{\ensuremath{\Sigma}}_{u}^{+}\ensuremath{\sim}b^{3}\mathrm{\ensuremath{\Pi}}_{u}$ electronic states. The resonances of the probe laser were observed by detecting the laser induced fluorescence from the target states to the $a^{3}\mathrm{\ensuremath{\Sigma}}_{u}^{+}$ triplet ground state. In addition, to confirm the triplet character as well as the vibrational quantum number assignment of the states, for selected resonances the fluorescence to the $a^{3}\mathrm{\ensuremath{\Sigma}}_{u}^{+}$ state was resolved and bound-free spectra were recorded. From the observed term values for each state potential-energy curves were constructed using the Rydberg-Klein-Rees method.

We report results of an experimental study of the changes in the alignment of the rotational angular momentum of diatomic molecules during elastic collisions. The experiment involved collisions of diatomic lithium molecules in the A1Σu+ excited electronic state with noble gas atoms (helium and argon) in a thermal gas phase sample. Polarized light for excitation was combined with the detection of polarization-specific fluorescence in order to achieve magnetic sublevel state selectivity. We also report results for rotationally inelastic collisions of Li2 in the lowest lying rotational levels of the A1Σu+v=5 vibrational state with noble gas atoms.

This paper reports a high-resolution experimental study and a numerical analysis of the Rb-2 6(1)Sigma(+)(g) ion-pair state. A large number of rovibrational term values spanning a wide range of the rotational and vibrational quantum numbers were measured using the optical-optical double-resonance technique. The set of term values was simulated with a model of a piecewise multiparameter potential-energy function based on the generalized splines. This function reproduces the experimental data with reasonable accuracy and, in addition, allows us to incorporate in the potential function the nontrivial features at longer internuclear range, such as multiple wells, predicted by the ab initio calculations.

This paper reports a high-resolution experimental study and a numerical analysis of the ${\mathrm{Rb}}_{2}\phantom{\rule{4pt}{0ex}}{6}^{1}{\mathrm{\ensuremath{\Sigma}}}_{g}^{+}$ ion-pair state. A large number of rovibrational term values spanning a wide range of the rotational and vibrational quantum numbers were measured using the optical-optical double-resonance technique. The set of term values was simulated with a model of a piecewise multiparameter potential-energy function based on the generalized splines. This function reproduces the experimental data with reasonable accuracy and, in addition, allows us to incorporate in the potential function the nontrivial features at longer internuclear range, such as multiple wells, predicted by the ab initio calculations.

This paper reports observations and analysis of the Rb-2 3(1)Pi(g) state. A total of 323 rovibrational term values spanning the range of the rotational quantum number J = 7 through 77 and the vibrational quantum number v = 2 through 23 (about 1/3 of the potential well depth) were measured using the optical-optical double resonance technique. The term values are simulated within a model of a piece-wise multi-parameter potential energy function based on the generalized splines. This function not only enables a reproduction of the experimental data with a reasonable quality but also approximates the available ab initio function in its whole range with a uniform accuracy. Published by AIP Publishing.

This paper reports observations and analysis of the Rb2 31Π g state. A total of 323 rovibrational term values spanning the range of the rotational quantum number J = 7 through 77 and the vibrational quantum number v = 2 through 23 (about 1/3 of the potential well depth) were measured using the optical-optical double resonance technique. The term values are simulated within a model of a piece-wise multi-parameter potential energy function based on the generalized splines. This function not only enables a reproduction of the experimental data with a reasonable quality but also approximates the available ab initio function in its whole range with a uniform accuracy.