0000000000444911

AUTHOR

E Karule

showing 4 related works from this author

Ionization of atomic hydrogen with up to four excess photons by circularly and linearly polarized light

2012

The above threshold ionization (ATI) is investigated for H in ns states. The total generalized cross sections are calculated for up to 4 excess photons using perturbation theory and modified Coulomb Green's function Sturmian expansion.

PhysicsHistoryPhotonHydrogenLinearly polarized lightAbove threshold ionizationchemistry.chemical_elementFunction (mathematics)Computer Science ApplicationsEducationchemistryIonizationCoulombPhysics::Atomic PhysicsAtomic physicsPerturbation theoryJournal of Physics: Conference Series
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The closed form of the second-order energy shift for the discrete spectrum of atomic hydrogen

2004

The closed form of the second-order energy shift for the discrete spectrum of atomic hydrogen is obtained, which allows us to evaluate the level shift in both cases, when the intermediate states are in continuum and in the discrete spectrum, except the resonances. The values of the second-order shift of the energy of the ground state calculated by us are in good agreement with those obtained by us and other authors using the nonperturbative Floquet method in average up to a radiation intensity of 1015 W cm−2.

Floquet theoryPhysicsContinuum (measurement)HydrogenContinuous spectrumchemistry.chemical_elementCondensed Matter PhysicsAtomic and Molecular Physics and OpticsDiscrete spectrumchemistryEnergy shiftAtomic physicsGround stateRadiant intensityJournal of Physics B: Atomic, Molecular and Optical Physics
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The general expression for the transition amplitude of two-photon ionization of atomic hydrogen

2003

Two-photon ionization of atomic hydrogen with an excess photon is revisited. The non-relativistic dipole approximation and Coulomb Green function (CGF) formalism are applied. Using the CGF Sturmian expansion straightforwardly, one gets the radial transition amplitude in the form of an infinite sum over Gauss hypergeometric functions which are polynomials. It is convergent if all intermediate states are in the discrete spectrum. In the case of two-photon ionization with an excess photon, when photoionization is also possible, intermediate states are in the continuum. We performed the explicit summation over intermediate states and got a simple general expression for the radial transition amp…

PhysicsAbove threshold ionizationPhotoionizationCondensed Matter PhysicsAtomic and Molecular Physics and OpticsPositroniumAmplitudeExcited stateQuantum mechanicsIonizationPhysics::Atomic PhysicsHypergeometric functionAtomic physicsGround stateJournal of Physics B: Atomic, Molecular and Optical Physics
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Above threshold ionization of atomic hydrogen inns states with up to four excess photons

2010

In a high-intensity laser field an atom can absorb more photons than the minimum necessary for ionization. It is known as above threshold ionization (ATI). Theoretically it is the most difficult case to handle as we have to consider transitions in continuum. To study ATI we use the perturbation theory and Green's function formalism. We have derived the modified two-term Coulomb Green's function (CGF) Sturmian expansion. In each term explicit summation over all intermediate states is carried out. The transition amplitude may be obtained in a closed form. The generalized cross sections are evaluated for the photoionization of atomic hydrogen in ns states with up to four excess photons. Calcul…

PhysicsPhotonAbove threshold ionizationPhotoionizationCondensed Matter PhysicsAtomic and Molecular Physics and OpticsWavelengthAmplitudeIonizationPhysics::Atomic and Molecular ClustersCoulombPhysics::Atomic PhysicsAtomic physicsCircular polarizationJournal of Physics B: Atomic, Molecular and Optical Physics
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