Probing dipole-forbidden autoionizing states by isolated attosecond pulses
| Autor: | Chu, Wei-Chun, Morishita, Toru, Lin, C. D. |
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| Rok vydání: | 2014 |
| Předmět: | |
| Zdroj: | Physical Review A 89, 033427 (2014) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevA.89.033427 |
| Popis: | We propose a general technique to retrieve the information of dipole-forbidden resonances in the autoionizing region. In the simulation, a helium atom is pumped by an isolated attosecond pulse in the extreme ultraviolet (EUV) combined with a few-femtosecond laser pulse. The excited wave packet consists of the $^1S$, $^1P$, and $^1D$ states, including the background continua, near the $2s2p(^1P)$ doubly excited state. The resultant electron spectra with various laser intensities and time delays between the EUV and laser pulses are obtained by a multilevel model and an ab initio time-dependent Schr\"odinger equation calculation. By taking the ab initio calculation as a "virtual measurement", the dipole-forbidden resonances are characterized by the multilevel model. We found that in contrast to the common assumption, the nonresonant coupling between the continua plays a significant role in the time-delayed electron spectra, which shows the correlation effect between photoelectrons before they leave the core. This technique takes the advantages of ultrashort pulses uniquely and would be a timely test for the current attosecond technology. Comment: 10 pages, 6 figures |
| Databáze: | arXiv |
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