Autoionizing Rydberg states of NO in strong electric fields

Abstract

We report on an investigation on autoionization of Rydberg electrons of the nitric oxide molecule in strong, static electric fields. The excitation was done via various rotational states of the A 2 ⌺ ϩ intermediate state (vЈϭ0) and with polarization parallel or perpendicular to the electric field. The splitting of the autoionizing Rydberg states into overlapping Stark manifolds is resolved for excitation above the saddlepoint created by the field. We observe that the competing decay between photoionization and predissociation can lead to an incorrect interpretation of threshold energy. The photoionization spectrum of NO Rydberg series attached to various rotational thresholds is very similar owing to weak rotational coupling. The experimental results are accurately simulated by quantum calculations based on multichannel quantum defect theory ͑MQDT͒. A more intuitive formulation of the average behavior of the photoionization cross section is developed that accounts for the suppression of ionization near the threshold due to competing predissociating channels.

Observation of the Stark effect in υ+= 0 Rydberg states of NO with a matrix-diagonalization analysis

“…The Stark effect in very high (n = 40-120) Rydberg states converging to the υ + = 0 ionization limit has been reported by Vrakking et al [16]. Warntjes et al [17] also investigated Rydberg states converging to the υ + = 0 ionization limit, but above the field-ionization limit. Our Stark studies are focused on intermediate (n = 25-32) Rydberg states converging to the υ + = 0 ionization limit, well below the field-ionization threshold in dc fields in the range 0-120 V cm −1 .…”

Probing double Rydberg wave packets in a helium atom with fast single-cycle pulses

“…The tiny energy spacing between adjacent Rydberg states makes it easier to generate spatially localized Rydberg wave packets [6,7]. Many experimental and theoretical studies on atoms with a single Rydberg wave packet have been conducted in the past few decades [8][9][10][11][12][13][14][15][16][17]. However, there are only a few experimental studies of the dynamics of double Rydberg wave packets [18][19][20][21][22].…”

The Stark effect in the predissociating Rydberg states of NO

“…Molecular Rydberg states are highly susceptible to the effects of external fields, and these effects are of importance in a number of new applications of Rydberg states [1], including the deceleration and deflection of Rydberg molecule beams [2][3][4][5][6], and recent experiments involving the scattering of Rydberg molecules at surfaces [7,8]. Previous spectroscopic studies of the Stark effect in molecular Rydberg states, primarily in H 2 [8][9][10], Li 2 [11] H 3 [12] and NO [13][14][15][16], have focused on either autoionising states which lie above the ionisation threshold, or those states that are sufficiently long lived and near to threshold to be detected by field ionisation. The requirement for long-lived character implies that the only states observed are those which are relatively immune to predissociation [16].…”