Rydberg States Of Principal Quantum Number Research Articles

Rovibrational characterization of XΣ+2B11H+ by the extrapolation of photoselected high Rydberg series in B11H

Optical-optical-optical triple-resonance spectroscopy of (11)BH isolates high Rydberg states that form series converging to rotational state specific ionization potentials in the vibrational levels of (11)BH(+) from nu(+)=0 through 4. Limits defined by a comprehensive fit of these series to state-detailed thresholds yield rovibrational constants describing the X (2)Sigma(+) state of (11)BH(+). The data provide a first determination of the vibrational-rotational interaction parameter alpha(e)=0.4821 cm(-1) and a more accurate estimate of omega(e)=2526.58 cm(-1) together with the higher-order anharmonic terms omega(e)x(e)=61.98 cm(-1) and omega(e)y(e)=-1.989 cm(-1). The deperturbation and global fit of series to state-detailed limits also yield a precise value of the adiabatic ionization potential of (11)BH of 79 120.3+/-0.1 cm(-1), or 9.810 33+/-1x10(-5) eV. High precision is afforded here by the use of graphical analysis techniques, narrow-bandwidth laser systems, and an analysis of newly observed, high principal quantum number Rydberg states that conform well with Hund's case (d) electron-core coupling limit.

Predissociation ofH3Rydberg states

A fast-beam spectrometer is used to investigate the photofragmentation and autoionization dynamics of laser-excited triatomic hydrogen molecules. The yield of neutral products from rapidly predissociated states of ${\mathrm{H}}_{3}$ is monitored in parallel with the field ionization signal. Using this spectrometer, we have measured the natural lifetime of low principal quantum number Rydberg states ${\mathrm{nsA}}_{1}^{\ensuremath{'}}$ and ${\mathrm{npE}}^{\ensuremath{'}}.$ For the ${3sA}_{1}^{\ensuremath{'}},$ ${4sA}_{1}^{\ensuremath{'}},$ and ${5sA}_{1}^{\ensuremath{'}}$ electronic states, we find lifetimes decreasing with increasing principal quantum number. This is unexpected for a Rydberg series and confirms the observations of a previous investigation. In addition, our experiments give direct evidence that even very high principal quantum number Rydberg states of ${\mathrm{H}}_{3}$ are selectively subject to strong predissociation. This process appreciably shortens their natural lifetimes. In the high principal quantum number $\mathrm{ns}$- and $\mathrm{nd}$ Rydberg series converging to the lowest ionization threshold of ${\mathrm{H}}_{3}$ we find a significant variation of the predissociation yield with principal quantum number and electronic angular momentum. Windows with enhanced predissociation in the Rydberg series are explained by nonadiabatic couplings of the laser-prepared initial states with the repulsive ground states surface mediated by vibrationally degenerate mode excited ${4pE}^{\ensuremath{'}}$ and ${5pE}^{\ensuremath{'}}$ states. The relevance of the ${\mathrm{H}}_{3}$ predissociation mechanisms for the dissociative recombination of ${\mathrm{H}}_{3}^{+}$ is discussed.

Electric Field Induced Dissociation of Molecules in Rydberg-like Highly Vibrationally Excited Ion-Pair States

The energetic thresholds for ion-pair photodissociation of diatomic oxygen $[{\mathrm{O}}_{2}+h\ensuremath{\nu}\ensuremath{\rightarrow}{\mathrm{O}}^{+}+{\mathrm{O}}^{\ensuremath{-}}(^{2}P_{3/2},^{2}P_{1/2})]$ were measured using a novel technique. The technique depends on the production and selective detection of highly vibrationally excited ion-pair states which last for at least $5\ensuremath{\mu}\mathrm{s}$ following single photon excitation from the ground electronic state of ${O}_{2}$. These ion-pair states are analogous to Rydberg states, and they may be dissociated by an electric field in a similar manner to the field ionization of high principal quantum number Rydberg states, allowing for their selective detection.

Spectroscopy of high n Rydberg states of the triatomic deuterium molecule D3

We report first investigations of high principal quantum number Rydberg states of the neutral triatomic deuterium molecule. The experiments were performed using a fast neutral beam photoionization spectrometer recently developed at Freiburg. A fast beam of metastable D3 molecules was created by charge transfer of a D3+ beam in cesium. Rydberg states of D3 were analyzed by pulsed-laser excitation using two-photon resonance-enhanced ionization, electric field ionization and autoionization. Our data identify the 2p 2A2″(N=K=0) state of D3 to be metastable with a lifetime of about 1 μs. The spectral lines following excitation in the ultraviolet spectral range were assigned to s-type and d-type Rydberg-series converging to vibrational ground state, symmetric stretch excited and degenerate mode excited D3+ ion states. By a combination of vibrationally diagonal and non-diagonal transitions, we determined the ionization potential, the symmetric stretch and degenerate mode vibrational frequencies of the 2p 2A2″ state in D3. The data give insight into the influence of the coupling between the Rydberg electron and the ion core on the potential energy surface.

Zero-kinetic-energy electron spectroscopy of the predissociating A2 Sigma + state of HBr+

The rotationally resolved zero-kinetic-energy electron spectra for the ${\mathit{v}}^{+}$=1, 2, and 3 vibrational levels of the predissociating ${\mathit{A}}^{2}$${\mathrm{\ensuremath{\Sigma}}}^{+}$ state of ${\mathrm{HBr}}^{+}$ are reported. The results for the rapidly predissociating ${\mathit{v}}^{+}$=2 and 3 levels show that the high principal quantum number Rydberg states involved in the zero-kinetic-energy spectroscopy are unperturbed by ion core fragmentation. These data demonstrate the general applicability of this technique for rotationally resolved photoelectron spectroscopy.