In this work, the interaction of a supersonic beam of toluene diluted in He with a resonant oscillating RF field is investigated both experimental and theoretically. It is shown how the resonant field induces a peak structure in the transverse beam profile which can be explained by the onset of molecular interferences. Specifically, the interaction of a toluene beam of 0.12 eV of translational energy with a resonant RF field of 1.12 kV/m amplitude, and -610 kV/m(2) of gradient at the horizontal plane, during 160 micros produces a series of maxima in the transverse beam profile. The observed structure was satisfactorily reproduced by a quantum interference model based on the interaction of two coherent superpositions induced by the resonant RF field. It appears the present experimental technique could be useful to investigate the spectroscopy and dynamical behavior of coherent beams of polar molecules.

Deflection of a cold supersonic NO beam seeded in He has been observed when these molecules interact with both static and a resonant oscillating electric field. The NO beam splits into two beams each one deflecting about 0.5° towards the positive and negative direction of the Stark field when the employed resonant frequency between the two Stark levels of the NO molecule is 1515 kHz. This deflection angle is about four orders of magnitude higher than the value one would expect from the NO dipole moment and the employed RF field gradient. This phenomenon suggests the possibility of a significant translational motion perpendicular to the beam axis, which is induced by the resonant RF electric field on the cold and high-density supersonic beam.

Deflection of a cold supersonic toluene beam seeded in He has been observed when these molecules interact with both a static and a resonant oscillating electric field. The toluene beam splits into two beams each one peaking at a deflection angle of 1 degree towards the positive and negative direction of the Stark field when the employed resonant frequency between the two Stark levels of the toluene molecule is 1411 kHz. This deflection angle is about four orders of magnitude higher than the value one would expect from the toluene dipole moment and the employed RF field gradient. Different hypothesis are suggested to explain the observed strong beam splitting including the possibility of transverse beam interferences induced by both the resonant RF field and the transverse uniform electric field. A theoretical model is presented based on molecular beam interferences induced by the resonant RF field which seems to account satisfactorily for the present observations.

This letter follows a previous publication from our group [C. Montero, A. Gonzalez Urena, J.O. Caceres, M. Morato, J. Najera, H.J. Loesch, European Physical Journal D 26, (2003) 261] where a significant depletion was observed when a supersonic NO beam seeded in He passed through a resonant RF field. Here the phenomenon has been confirmed using different conditions. It is shown how the observed depletion depends on: (i) the rotational NO quantum numbers: (ii) the strength of both the static and RF electric fields. (c) 2006 Elsevier B.V. All rights reserved.

The interaction between a NO supersonic beam and a resonant radio frequency (RF) field is investigated using laser ionization coupled to imaging techniques. It is shown how the resonant interaction leads to a beam splitting of +/-0.2 degrees toward both positive and negative direction perpendicular to the beam propagation axis. This phenomenon is rationalized using a model based on molecular interferences produced by the action of the resonant RF electric field.

In previous experimental works from this laboratory two unexpected phenomena were reported: (i) a depletion of ca. 40% in the total intensity of a pulsed He seeded NO beam when these molecules passed a homogeneous and a resonant oscillating RF electric field and (ii) a beam splitting of ca. 0.5° when the transverse beam profile is measured, under the same experimental conditions. In this work a model based on molecular beam interferences is introduced which satisfactorily accounts for these two observations. It is shown how the experimental set-up a simple device used as C-field in early molecular beam electric resonance experiments, can be employed as molecular interferometer to investigate matter–wave interferences in beams of polar molecules.

Using our spectroscopic technique based on molecular beam electric resonance without A and B fields [Chem. Phys. Lett. 341 (2001) 495] depletion spectra of both NO and (NO)2 were measured. The experimental results show an energy shift of the order of 10−8 cm−1 between the maxima of their (central) band spectra. This resolution enables to estimate changes in the NO dipole moment of the order of 0.6%, as this molecule forms the dimer. It is suggested that this technique could be used to investigate molecular rearrangements in gas-phase dynamical processes as well as to resolve variations in molecular bond distances in solvation or cluster processes.

We report on a novel phenomenon observed during the passage of a pulsed NO beam seeded in He through a combined homogeneous, static electric and RF field, denoted as C-field in a standard molecular beam electric resonance (MBER) experiment. Although we refrain from the state selective A- and B-fields, which are considered crucial for a MBER experiment, the transmitted intensity exhibits as a function of the RF frequency conspicuous dips at resonance frequencies that depend strictly linearly on the static field strength E 0. Their spectral width is by a factor of 4 smaller than the time of flight broadening. Both, the resonance frequencies and their linear field dependence can be precisely predicted applying a simple expression for the Stark effect to a \(\Delta M = \pm 1\) transition of a single rotational state (J = 3/2) of the electronic ground state \(^2\Pi_{1/2}\). However, this formula is valid only in the high field limit (E 0 > 1000 kV/m) while the employed field (E 0 = 1.47 kV/m) was in the extreme low field domain where the large \(\Lambda\) type doubling and hyperfine coupling lead to a purely quadratic Stark effect. We assume that the phenomenon is due to a yet unknown collective rather than to an isolated particle process.