Contribution of forbidden orbits in the photoabsorption spectra of atoms and molecules in a magnetic field

• Main Authors: Matzkin, A, Dando, P. A, Monteiro, T. S
• Format: Journal Article
• Language: English
• Published: 18.07.2002
• Subjects: Physics - Atomic Physics
• DOI: 10.48550/arxiv.physics/0207072

Phys. Rev. A 67, 023402 (2003). In a previous work [Phys. Rev. A \textbf{66}, 0134XX (2002)] we noted a partial disagreement between quantum R-matrix and semiclassical calculations of photoabsorption spectra of molecules in a magnetic field. We show this disagreement is due to a non-vanishing contribution of processes which are forbidden according to the usual semiclassical formalism. Formulas to include these processes are obtained by using a refined stationary phase approximation. The resulting higher order in $\hbar$ contributions also account for previously unexplained ``recurrences without closed-orbits''. Quantum and semiclassical photoabsorption spectra for Rydberg atoms and molecules in a magnetic field are calculated and compared to assess the validity of the first-order forbidden orbit contributions.