# G. GasaneoNational Scientific and Technical Research Council | conicet · CCT Bahia Blanca

G. Gasaneo

Professor

Currently I´m working on neuroscience topics, particularly modeling attentional and reading processes in children.

## About

148

Publications

12,158

Reads

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1,465

Citations

Citations since 2016

Introduction

Currently I´m working on neuroscience topics, particularly modeling of attentional and reading processes in children. We use generalized Langevin equations together with multifractal analysis, complexity-entropy analysis among others.

## Publications

Publications (148)

Eye tracking is being increasingly used as a more powerful diagnosis instrument when compared with traditional pen-and-paper tests in psychopedagogy and psychology. This technology may significantly improve neurocognitive assessments in gathering indirect latent information about the subjects’ performance. However, the meaning and implications of t...

Starting with a proposal to model horizontal eye movements, we study the parameters involved in it. Particularly, we investigate the values that best fit the parameters describing the activation force responsible for horizontal saccades, independently of the task being performed. The fitting process is based on data sets gathered with an eye tracke...

We propose a novel adaptation of permutation entropy analysis applied to eye-tracking data. Eye movements arising during cognitive tasks are characterized as sequences of trajectories within a space of ordinal trajectory patterns, thus taking advantage of recent advancements in the study of complex processes in terms of statistical complexity. Resu...

In a recent letter [S. Bouzat et al., Phys. Rev. Lett. 120, 178101 (2018)], a mathematical model for eyeball and pupil motion was developed allowing for the understanding of the postsaccadic oscillations (PSO) as inertial effects. The model assumes that the inner part of the iris, which defines the pupil, moves driven by inertial forces induced by...

In this paper we discuss the implementation of scaling functions and wavelets based on Generalized Sturmian Functions (GSF). When dealing with finite dimensional spaces, the completeness relation of the GSF basis generates localized functions in two coordinates. By fixing one of the coordinates on particular points one defines the corresponding sca...

In this contribution, we perform detrended fluctuation analysis on eye movement data obtained using an eye tracker with different experimentation subjects performing a set of distinct cognitive tasks. We define three different paradigms: spotting differences among two similar pictures, answering questions in a multiple choice questionnaire, and per...

In this paper we employ a driven harmonic oscillator to satisfactorily describe data corresponding to ocular movements produced during a visual search task. The data is acquired with an EyeLink 1000. We describe the details of the oscillations in the eye’s rotation angles in between 4 and 40° observed before and after the saccadic and microsaccadic...

The use of eye-tracking techniques is becoming rapidly extended because of its relevance for acquiring information about cognition and behavior. Recent studies indicate that a correct characterization of the motion of the pupil inside the eyeball is needed, because this motion influences the eye-tracking results. In this work we face this problem a...

The derivatives of eight Horn hypergeometric functions [four Appell F1, F2, F3, and F4, and four (degenerate) confluent Φ1, Φ2, Ψ1, and Ξ1] with respect to their parameters are studied. The first derivatives are expressed, systematically, as triple infinite summations or, alternatively, as single summations of two-variable Kampé de Fériet functions...

We study theoretically the double ionization of helium by 6 MeV proton impact. For such fast projectiles, when considering the projectile-target interaction to first order, the four-body Schrödinger equation reduces to solving a three-body driven equation. We solve it with a generalized Sturmian functions approach and, without evaluating a transiti...

In this paper we have addressed the question of whether a simple set of functions being the solution of a model, namely the damped harmonic oscillator with a general driving force, can satisfactorily describe data corresponding to ocular movements produced during a visual search task. Taking advantage of its mathematical tractability, we first focu...

In this work we present a novel implementation of the Generalized Sturmian Functions in the time-dependent frame to numerically solve the time-dependent Schrödinger equation. We study the effect of the confinement of H atom in a fullerene cage for the 1s → 2p resonant transition of the atom interacting with a finite laser pulse, calculating the pop...

We investigate the two-body Coulomb radial problem, providing extensions of known results and establishing a novel connection to orthogonal polynomials. The expansion in Laguerre-type functions of positive energy Coulomb solutions allows one to separate out the radial coordinate from the physical parameters. For the regular Coulomb wave function an...

We give a detailed account of an $\it{ab}$ $\it{initio}$ spectral approach for the calculation of energy spectra of two active electron atoms in a system of hyperspherical coordinates. In this system of coordinates, the Hamiltonian has the same structure as the one of atomic hydrogen with the Coulomb potential expressed in terms of a hyperradius an...

Abstract In this contribution we study mathematical properties of scattering solutions of Schrödinger-type equations with nondecaying, outgoing type, driven terms. We analyze in some details the two-body frame, where an analytical treatment is possible, and find how the scattering solution is expected to contain a beating type structure. The analyt...

The description with traditional methods of the single or multiple ionization of atoms and molecules by two or more successive photons requires some special treatment. Difficulties occur when a spatially non-decaying driven term appears in the Schrödinger-like non-homogeneous equation for the scattering wave function. We propose using the intrinsic...

We present theoretical and experimental fully differential cross sections, in coplanar scattering geometry, for the double ionization of helium by electron impacting at 2 keV. The observed structures for both equal and unequal sharing of the excess energy are analyzed. Although the incident energy could, in principle, be regarded as high enough for...

An accurate theoretical description of photoionization processes is necessary in order to understand a wide variety of physical and chemical phenomena and allows one to test correlation effects of the target. Compared to the case of many-electron atoms several extra challenges occur for molecules. The scattering problem is generally multicenter and...

We compare the physical information contained in the Temkin-Poet (TP) scattering wave function representing electron-impact ionization of hydrogen, calculated by the convergent close-coupling (CCC) and generalized Sturmian function (GSF) methodologies. The idea is to show that the ionization cross section can be extracted from the wave functions th...

Functions of a new type are proposed which can be used as basis functions in the description of states of the continuous spectrum of a Coulomb system of three particles. The basis functions are represented in the form of a convolution of two quasi Sturmian functions, each of which satisfies the inhomogeneous Schrödinger equation. The asymptotic for...

We present ab initio calculations for the double ionization of helium by fast proton impact, using the generalized-Sturmian-functions methodology and within a perturbative treatment of the projectile-target interaction. The cross-section information is extracted from the asymptotic behavior of the numerical three-body function that describes the em...

In this work we study the effect of fullerene confinement on the triple differential cross section (TDCS) for double ionization of atoms. We compare the results corresponding to the free case with single cage C60 and two cage C60@C240 confinement.

In this work we study the effect of the confinement of H atom in a fullerene cage for the 1s→2p resonant transition of the atom interacting with a laser pulse. We present a novell implementation of the Generalized Sturmian Functions in the time-dependent frame to numerically solve this problem calculating the population of bound states and spectral...

Quasi-Sturmian functions are an alternative set of basis functions useful to describe time-independent three body scattering problems. Their analytical closed form, for the Coulomb case, and some of their properties are presented here in hyperspherical coordinates.

We explore the implementation of generalized Sturmian functions for the study of ionization of molecules by photon or electron impact. A first part is devoted to finding a good enough description of the molecular model scattering potential and imposing accurate asymptotic boundary conditions to the molecular continuum wave functions. A second part...

We present fully differentiated cross sections for the Helium double ionization by neutronic impact. From our theoretical results we observe the underlying mechanisms that lead to the breakup of the target.

We apply the Generalized Sturmian Functions method to the double ionization of Helium by fast electron and proton impact, obtaining fully differentiated cross sections which allow for a better understanding of the few-particle dynamics.

In this work we present the application of the Generalized Sturmian basis to the process of photonionization by an electromagnetic pulse in the framework of a perturbation theory. The Generalized Sturmian basis have the proper asymptotic behavior allowing us to extract the transition amplitudes directly from the coefficients of expansion.

The driven equation describing an (e, 3e) process on helium in the framework of the Temkin-Poet model is solved numerically using expansions of Convoluted Quasi Sturmian functions. As we observe first that the convergence rate of the solution is rather poor, we propose to significantly improve the expansion by introducing a phase factor correspondi...

In this work we study the double photoionization of helium induced by low intensities laser fields in the regime where only one photon absorption occurs. The method proposed here is based on a Generalized Sturmian Functions (GSF) spectral approach which allows the imposition of outgoing boundary conditions for both ejected electrons. These, in turn...

We explore the implementation of generalized Sturmian functions for the study of ionization of molecules by photon or electron impact. A first part is devoted to finding a good enough description of the molecular model scattering potential and imposing accurate asymptotic boundary conditions to the molecular continuum wave functions. A second part...

The Generalized Sturmian Functions method aims to deal with atomic physics problems. It has seen application to two and three–body problems, and its flexibility enables one to work with bound systems as well as with particles in the continuum. In the present contribution we analyze how the method expands the atomic double continuum in collision pro...

The double ionization of helium by high energy electron impact is studied. The corresponding four-body Schrödinger equation is transformed into a set of driven equations containing successive orders in the projectile–target interaction. The first order driven equation is solved with a generalized Sturmian functions approach. The transition amplitud...

We compute fully differential cross sections for double ionization of helium by electrons, within the high-impact-energy and low-momentum transfer regimes, using the generalized Sturmian functions approach. Our results are converged relative to the total angular momentum and variable domain size. The method shows very good agreement with convergent...

Quasi-Sturm (QS) functions are proposed as basis functions in a description of the states of the continuous spectrum of a quantum system. A representation of QS functions in closed analytical form is obtained. The advantages of the method are illustrated by an example of the two-particle scattering problem.

Single photoionization cross sections for two different ground state orbitals of the molecule CH4 are presented. An angular averaged molecular model potential is used to represent the interaction of the ionized electrons, whose continuum wave functions are calculated within a generalized Sturmian functions approach.

The application of generalized Sturmian functions to the study of single photoionization of different atomic and molecular systems is illustrated using model potentials. Sturmian functions have been used successfully to study single and double ionization by electron impact on He, while their implementation to molecular systems is still under develo...

In this contribution we study the still open problem of the double ionization of Helium by fast electrons, within the small momentum trans-fer regime. Despite the many theoretical efforts, no good or even acceptable matching was re-ported with the experimental data on the fully differential cross section (FDCS) [1]. Moreover, different theories dis...

We introduce and study two-body Quasi Sturmian functions which are proposed as basis functions for applications in three-body scattering problems. They are solutions of a two-body non-homogeneous Schrodinger equation. We present different analytic expressions, including asymptotic behaviors, for the pure Coulomb potential with a driven term involvi...

Three aspects of the Generalized Sturmian Function method are discussed, adding to the flexibility of the formulation.

Two-electron atoms in screened and exponential cosine screened Coulomb potentials are studied. We have calculated within a Configuration Interaction approach, the ground and first excited states energies, and other mean values, for H−, He and Li+. We analyze their evolution with the screening parameters, and provide practical fits which allow for a...

Quasi-Sturmians, a mainly analytical tool for solving scattering problems, are introduced and their performance is compared with the Generalized Sturmian Function method.

An hyperspherical Sturmian approach recently developed for three-body break-up processes is presented. To test several of its features, the method is applied to two simplified models. Excellent agreement is found when compared with the results of an analytically solvable problem. For the Temkin-Poet model of the double ionization of He by high ener...

We extend the Angular Correlated Configuration Interaction method to two confined correlated electrons confined by harmonic potentials.

The double ionization of helium by high energy electron impact is investigated. The pure four-body Coulomb problem may be reduced to a three-body one in accordance with the use of the first Born approximation. Even within this frame, major unexplained discrepancies subsist between several theoretical descriptions, and with available absolute experi...

In a recent contribution our group proposed a perturbative approach to deal with the open problem of double ionization of helium by electron impact. The goal of this work is to delve into the physics of the scattering function, and provide evidence of the nature of the single-ionization channels present in the three-body wave function. We show that...

The study of structure and collision processes of three- and four-body problems has seen an extraordinary progress in the last decades. This progress has been in part associated to the incredible fast growth of the computer capabilities. However, the tools used to solve structure problems are different from those corresponding to the treatment of c...

The second Born approximation is often used, particularly when we study double processes such as the ionization–excitation and the double ionization of atoms and molecules by charged particles. But when we apply this approximation, it needs the knowledge of all excited states of the target. In this study, we apply the second Born approximation by u...

In this paper the double ionization of helium by high-energy electron impact is studied. The corresponding four-body Schrödinger equation is transformed into a set of driven equations containing successive orders in the projectile-target interaction. The transition amplitude obtained from the asymptotic limit of the first-order solution is shown to...

A hyperspherical Sturmian approach recently developed for three-body break-up processes is tested through an analytically solvable S-wave model. The scattering process is represented by a non-homogeneous Schrödinger equation in which the driven term is given by a Coulomb-like interaction multiplied by the product of a continuum wavefunction and a b...

The angularly correlated basis functions proposed by Gasaneo and Ancarani (Phys Rev, A 77:012705, 2008) are used to construct approximated wavefunctions, satisfying all two-body cusp conditions, for several three-body systems.
The focus here is on the study of the following negatively charged hydrogen-like ions: ∞ H − , 1H − , D − , T − and Mu − ,...

We introduce explicitly correlated Sturmian functions with appropriate
boundary conditions to deal with both bound and scattering states of
three-body systems.

We consider two different Sturmian Function (SF) expansions to describe
three-body break-up wave functions having outgoing flux behavior: one in
hyper-spherical coordinates (ρ and α) and one in spherical
coordinates (r1 and r2). We compare the
convergence rates of the two treatment, and relate the analysis to
geometry aspects of the problem.

Our aim is to study the ionization-excitation and (e,3e) processes of
the He atom. The high energy first Born-approximation transition
amplitudes are obtained from the asymptotic limit of the exact
three-body wave function. This wave function is obtained by solving a
driven Schrödinger equation which contains the double bound He wave
function. The...

The Configuration Interaction method with uncorrelated Sturmian basis functions is applied to describe a variety of atomic and molecular three-body systems.

In this work we present the application of the generalized Sturmian
basis to the single photon - double ionization of atoms.

We test a new methodology to obtain a Sturmian basis set using B-spline
expansion of arbitrary order and imposing the correct boundary
conditions for both negative and positive energy domains. The Sturmians
can be applied to solve both atomic systems, which are transformed into
an eigenvalue problem, and scattering processes, which leads to a
compl...

We extend the Angular Correlated Configuration Interaction method to two-electron atoms placed in a plasma environment.

We investigate the limiting procedures to obtain Coulomb interactions
from short-range potentials. The application of standard techniques used
for the two-body case (exponential and sharp cutoff) to the three-body
break-up problem is illustrated numerically by considering the
Temkin-Poet (TP) model of e-H processes.

An analytically solvable model for three particles break up processes is
presented. The scattering process is represented by a non-homogeneous
Schrödinger equation where the driven term is given by a
Yukawa-like interaction multiplied by the product of a continuum wave
function and a bound state in the particles coordinates. A closed form
solution...

An analytically solvable S-wave model for three particles break-up
processes is presented. The scattering process is represented by a non-homogeneous
Coulombic Schrödinger equation where the driven term is given by a Coulomb-like
interaction multiplied by the product of a continuum wave function and a bound state in
the particles coordinates. The c...

A methodology based on generalized Sturmian functions is put forward to
solve two- and three-body scattering problems. It uses a spectral method
which allows for the inclusion of the correct asymptotic behavior when
solving the associated driven Schr¨odinger equation. For the two-body case,
we demonstrate the equivalence between the exterior comple...

One way of extracting single differential cross sections (SDCS) for the
electron-hydrogen ionization process is based on using the quantum
mechanical flux operator evaluated at asymptotic distances. This
procedure is formally correct; however, numerical evaluations are
necessarily performed at finite distances. As a consequence, unphysical
oscillat...

We study some formal aspects of the exterior complex scaling (ECS) approach when imple-mented for both short and long-range potentials. In particular, we focus on the inconsistencies related to the requirement of an artificial cut-off of the potential in order to avoid exponential divergencies due to the complex rotation. For the pure two-body Coul...

A methodology based on generalized Sturmian functions is put forward to solve two- and three-body scattering problems. It uses a spectral method which allows for the inclusion of the correct asymptotic behavior when solving the associated driven Schrödinger equation. For the two-body case, we demonstrate the equivalence between the exterior complex...

We study some mathematical properties of generalized Sturmian functions which are solutions of a Schrödinger-like equation supplemented by two boundary conditions. These generalized functions, for any value of the energy, are defined in terms of the magnitude of the potential. One of the boundary conditions is imposed at the origin of the coordinat...

n1,3S (n = 1 − 4) states for atomic three-body systems are studied with the Angular Correlated Configuration Interaction method. A recently proposed angularly correlated basis set is used to construct, simultaneously and with a single diagonalization, ground and excited states wave functions which: (i) satisfy exactly Kato cusp conditions at the tw...

An analytically solvable three-body collision system (s wave) model is used to test two different theoretical methods. The first one is a configuration interaction expansion of the scattering wave function using a basis set of Generalized Sturmian Functions (GSF) with purely outgoing flux (CISF), introduced recently in A. L. Frapicinni, J. M. Randa...

One way to describe ion-atom break-up processes consists in splitting
the total wave function as
&+circ;=ψ0+ψsc^+, where
ψ0 is an asymptotically prepared initial state and
ψsc^+ is the scattering solution. Adequate asymptotic
behavior should be imposed, and hyperspherical coordinates (,) are well
adapted for this purpose. A Sturmian approach in the...

A methodology based on generalized Sturmian functions is put forward to
solve two- and three-body scattering problems. It uses a spectral method
which allows for the inclusion of the correct asymptotic behavior when
solving the associated driven Schr"odinger equation. For the two--body
case we demonstrate the equivalence between the ECS and the Stu...