Search Results
Looking inside the tunnelling barrier: II. Co- and counter-rotating electrons at the ‘tunnelling exit’
2018-08-03, Kaushal, Jivesh, Smirnova, Olga
The initial conditions for electron trajectories at the exit from the tunnelling barrier are often used in strong field models, for example to bridge the first and the second steps of the three-step model celebrated in this issue. Since the analytical R-matrix theory does not rely on the three-step model or the concept of the tunnelling barrier in coordinate space, obtaining the initial conditions for electron trajectories at the barrier exit is, strictly speaking, not necessary to calculate standard observables. Not necessary, but possible—especially when motivated by the occasion of this issue. The opportunity to evaluate such initial conditions emerges as a corollary of analysing sub-barrier kinematics, which includes the interplay of laser and Coulomb fields on the sub-cycle scale (see the companion paper I). We apply our results to discuss the difference in such initial conditions for co- and counter-rotating electrons liberated during strong field ionisation. We derive quantum orbits and classical trajectories describing ionization dynamics of co- and counter-rotating electrons in long-range potentials.
Enantio-sensitive unidirectional light bending
2021, Ayuso, David, Ordonez, Andres F., Decleva, Piero, Ivanov, Misha, Smirnova, Olga
Structured light, which exhibits nontrivial intensity, phase, and polarization patterns in space, has key applications ranging from imaging and 3D micromanipulation to classical and quantum communication. However, to date, its application to molecular chirality has been limited by the weakness of magnetic interactions. Here we structure light’s local handedness in space to introduce and realize an enantio-sensitive interferometer for efficient chiral recognition without magnetic interactions, which can be seen as an enantio-sensitive version of Young’s double slit experiment. Upon interaction with isotropic chiral media, such chirality-structured light effectively creates chiral emitters of opposite handedness, located at different positions in space. We show that if the distribution of light’s handedness breaks left-right symmetry, the interference of these chiral emitters leads to unidirectional bending of the emitted light, in opposite directions in media of opposite handedness, even if the number of the left-handed and right-handed emitters excited in the medium is exactly the same. Our work introduces the concepts of polarization of chirality and chirality-polarized light, exposes the immense potential of sculpting light’s local chirality, and offers novel opportunities for efficient chiral discrimination, enantio-sensitive optical molecular fingerprinting and imaging on ultrafast time scales.
A molecular clock for autoionization decay
2017-06-14, Medišauskas, Lukas, Bello, Roger Y., Palacios, Alicia, González-Castrillo, Alberto, Morales, Felipe, Plimak, Lev, Smirnova, Olga, Martín, Fernando, Ivanov, Misha Yu
The ultrafast decay of highly excited electronic states is resolved with a molecular clock technique, using the vibrational motion associated to the ionic bound states as a time-reference. We demonstrate the validity of the method in the context of autoionization of the hydrogen molecule, where nearly exact full dimensional ab-initio calculations are available. The vibrationally resolved photoionization spectrum provides a time–energy mapping of the autoionization process into the bound states that is used to fully reconstruct the decay in time. A resolution of a fraction of the vibrational period is achieved. Since no assumptions are made on the underlying coupled electron–nuclear dynamics, the reconstruction procedure can be applied to describe the general problem of the decay of highly excited states in other molecular targets.
Attosecond recorder of the polarization state of light
2018, Jiménez-Galán, Álvaro, Dixit, Gopal, Patchkovskii, Serguei, Smirnova, Olga, Morales, Felipe, Ivanov, Misha
High harmonic generation in multi-color laser fields opens the opportunity of generating isolated attosecond pulses with high ellipticity. Such pulses hold the potential for time-resolving chiral electronic, magnetization, and spin dynamics at their natural timescale. However, this potential cannot be realized without characterizing the exact polarization state of light on the attosecond timescale. Here we propose and numerically demonstrate a complete solution of this problem. Our solution exploits the extrinsic two-dimensional chirality induced in an atom interacting with the chiral attosecond pulse and a linearly polarized infrared probe. The resulting asymmetry in the photoelectron spectra allows to reconstruct the complete polarization state of the attosecond pulse, including its possible time dependence. The challenging problem of distinguishing circularly polarized, partially polarized, or unpolarized pulses in the extreme ultraviolet range is also resolved. We expect this approach to become the core ingredient for attosecond measurements of chiral-sensitive processes in gas and condensed phase.
Role of electronic correlations in photoionization of NO2 in the vicinity of the 2A1/2B2 conical intersection
2017, Brambila, Danilo S., Harvey, Alex G., Houfek, Karel, Mašín, Zdeněk, Smirnova, Olga
We present the first ab initio multi-channel photoionization calculations for NO2 in the vicinity of the 2A1/2B2 conical intersection, for a range of nuclear geometries, using our newly developed set of tools based on the ab initio multichannel R-matrix method. Electronic correlation is included in both the neutral and the scattering states of the molecule via configuration interaction. Configuration mixing is especially important around conical intersections and avoided crossings, both pertinent for NO2, and manifests itself via significant variations in photoelectron angular distributions. The method allows for a balanced and accurate description of the photoionization/photorecombination for a number of different ionic channels in a wide range of photoelectron energies up to 100 eV. Proper account of electron correlations is crucial for interpreting time-resolved signals in photoelectron spectroscopy and high harmonic generation (HHG) from polyatomic molecules.
Strong-field control and enhancement of chiral response in bi-elliptical high-order harmonic generation: an analytical model
2018-05-30, Ayuso, David, Decleva, Piero, Patchkovskii, Serguei, Smirnova, Olga
The generation of high-order harmonics in a medium of chiral molecules driven by intense bi-elliptical laser fields can lead to strong chiroptical response in a broad range of harmonic numbers and ellipticities (Ayuso et al 2018 J. Phys. B: At. Mol. Opt. Phys. 51 06LT01). Here we present a comprehensive analytical model that can describe the most relevant features arising in the high-order harmonic spectra of chiral molecules driven by strong bi-elliptical fields. Our model recovers the physical picture underlying chiral high-order harmonic generation (HHG) based on ultrafast chiral hole motion and identifies the rotationally invariant molecular pseudoscalars responsible for chiral dynamics. Using the chiral molecule propylene oxide as an example, we show that one can control and enhance the chiral response in bi-elliptical HHG by tailoring the driving field, in particular by tuning its frequency, intensity and ellipticity, exploiting a suppression mechanism of achiral background based on the linear Stark effect.
NO2molecular frame photoelectron angular distributions for a range of geometries using the R-matrix method
2015, Brambila, Danilo S., Harvey, Alex G., Mašín, Zdeněk, Smirnova, Olga
We present R-matrix calculations of photoionization from NO2, resolved in energy, angle, and both neutral and ionic state, for a range of molecular geometries, including in the vicinity of the 2A1/2B2 conical intersection.
Roadmap on photonic, electronic and atomic collision physics: I. Light-matter interaction
2019, Ueda, Kiyoshi, Sokell, Emma, Schippers, Stefan, Aumayr, Friedrich, Sadeghpour, Hossein, Burgdörfer, Joachim, Lemell, Christoph, Tong, Xiao-Min, Pfeifer, Thomas, Calegari, Francesca, Palacios, Alicia, Martin, Fernando, Corkum, Paul, Sansone, Giuseppe, Gryzlova, Elena V., Grum-Grzhimailo, Alexei N., Piancastelli, Maria Novella, Weber, Peter M., Steinle, Tobias, Amini, Kasra, Biegert, Jens, Berrah, Nora, Kukk, Edwin, Santra, Robin, Müller, Alfred, Dowek, Danielle, Lucchese, Robert R., McCurdy, C. William, Bolognesi, Paola, Avaldi, Lorenzo, Jahnke, Till, Schöffler, Markus S., Dörner, Reinhard, Mairesse, Yann, Nahon, Laurent, Smirnova, Olga, Schlathölter, Thomas, Campbell, Eleanor E.B., Rost, Jan-Michael, Meyer, Michael, Tanaka, Kazuo A.
We publish three Roadmaps on photonic, electronic and atomic collision physics in order to celebrate the 60th anniversary of the ICPEAC conference. In Roadmap I, we focus on the light-matter interaction. In this area, studies of ultrafast electronic and molecular dynamics have been rapidly growing, with the advent of new light sources such as attosecond lasers and x-ray free electron lasers. In parallel, experiments with established synchrotron radiation sources and femtosecond lasers using cutting-edge detection schemes are revealing new scientific insights that have never been exploited. Relevant theories are also being rapidly developed. Target samples for photon-impact experiments are expanding from atoms and small molecules to complex systems such as biomolecules, fullerene, clusters and solids. This Roadmap aims to look back along the road, explaining the development of these fields, and look forward, collecting contributions from twenty leading groups from the field. © 2019 IOP Publishing Ltd.
Chiral dichroism in bi-elliptical high-order harmonic generation
2018-02-28, Ayuso, David, Decleva, Piero, Patchkovskii, Serguei, Smirnova, Olga
The application of strong bi-elliptically polarized laser fields to the generation of high-order harmonics in organic molecules offers exceptional opportunities for chiral recognition and chiral discrimination. These fields are made by combining an elliptically polarized fundamental, typically in the infrared range, with its counter-rotating second harmonic. Here we present a theoretical study of the harmonic emission from the chiral molecule propylene oxide in bi-elliptical fields. Our calculations include, for the first time in such a complex system, accurate photorecomination matrix elements, evaluated using the static-exchange density functional theory method. We show that bi-elliptical light can induce strong chiral dichroism in the harmonic spectra of chiral molecules in a broad range of harmonic numbers and ellipticities.
Recent developments in R-matrix applications to molecular processes
2015, Mašín, Zdeněk, Harvey, Alex, Houfek, Karel, Brambila, Danilo S., Morales, Felipe, Gorfinkiel, Jimena D., Tennyson, Jonathan, Smirnova, Olga
We report on recent developments of the UKRmol suite, an implementation of the molecular R- matrix method and present examples of the calculations (e.g. electron scattering, photoionization, high harmonic generation, etc.) it has enabled.