TY - JOUR

T1 - R-matrix-Floquet theory of multiphoton processes: VIII. A linear equations method

AU - Glass, D.H.

AU - Burke, P.G.

AU - Van Der Hart, H.W.

AU - Noble, C.J.

PY - 1997/9/14

Y1 - 1997/9/14

N2 - A new linear equations method for calculating the R-matrix, which arises in the R-matrix-Floquet theory of multiphoton processes, is introduced. This method replaces the diagonalization of the Floquet Hamiltonian matrix by the solution of a set of linear simultaneous equations which are solved, in the present work, by the conjugate gradient method. This approach uses considerably less computer memory and can be readily ported onto parallel computers. It will thus enable much larger problems of current interest to be treated. This new method is tested by applying it to three-photon ionization of helium at frequencies where double resonances with a bound state and autoionizing states are important. Finally, an alternative linear equations method, which avoids the explicit calculation of the R-matrix by incorporating the boundary conditions directly, is described in an appendix.

AB - A new linear equations method for calculating the R-matrix, which arises in the R-matrix-Floquet theory of multiphoton processes, is introduced. This method replaces the diagonalization of the Floquet Hamiltonian matrix by the solution of a set of linear simultaneous equations which are solved, in the present work, by the conjugate gradient method. This approach uses considerably less computer memory and can be readily ported onto parallel computers. It will thus enable much larger problems of current interest to be treated. This new method is tested by applying it to three-photon ionization of helium at frequencies where double resonances with a bound state and autoionizing states are important. Finally, an alternative linear equations method, which avoids the explicit calculation of the R-matrix by incorporating the boundary conditions directly, is described in an appendix.

UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0031236332&partnerID=MN8TOARS

U2 - 10.1088/0953-4075/30/17/011

DO - 10.1088/0953-4075/30/17/011

M3 - Article

SN - 0953-4075

VL - 30

SP - 3801

EP - 3819

JO - Journal of Physics B: Atomic, Molecular & Optical Physics

JF - Journal of Physics B: Atomic, Molecular & Optical Physics

IS - 17

ER -