The calculation of accurate photoelectron spectra (PES) for strong-field laser-atom experiments is a demanding computational task, even in single-active-electron approximation. The QPROP code, published in 2006, has been extended in 2016 in order to provide the possibility to calculate PES using the so-called t-SURFF approach [L. Tao, A. Scrinzi, New J. Phys. 14, 013021 (2012)]. In t-SURFF, the flux through a surface while the laser is on is monitored. Calculating PES from this flux through a surface enclosing a relatively small computational grid is much more efficient than calculating it from the widely spread wavefunction at the end of the laser pulse on a much larger grid. However, the smaller the minimum photoelectron energy of interest is, the more post-propagation after the actual laser pulse is necessary. This drawback of t-SURFF has been overcome by Morales et al. [F. Morales, T. Bredtmann, S. Patchkovskii, J. Phys. B: At. Mol. Opt. Phys. 49, 245001 (2016)] by noticing that the propagation of the wavefunction from the end of the laser pulse to infinity can be performed very efficiently in a single step. In this work, we introduce QPROP 3.0, in which this single-step post-propagation (dubbed i-SURFV) is added. Examples, illustrating the new feature, are discussed. A few other improvements, concerning mainly the parameter files, are also explained.

中文翻译：

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Qprop 可以更快地计算光电子谱

强场激光原子实验的精确光电子能谱 (PES) 的计算是一项艰巨的计算任务，即使在单活性电子近似中也是如此。2006 年发布的 QPROP 代码已于 2016 年扩展，以便提供使用所谓的 t-SURFF 方法计算 PES 的可能性 [L. Tao, A. Scrinzi, New J. Phys. 14, 013021 (2012)]。在 t-SURFF 中，当激光打开时通过表面的通量被监控。从这个通量通过一个封闭一个相对较小的计算网格的表面计算 PES 比在一个更大的网格上从激光脉冲结束时广泛传播的波函数计算它的效率要高得多。然而，感兴趣的最小光电子能量越小，在实际激光脉冲之后需要越多的后传播。Morales 等人已经克服了 t-SURFF 的这个缺点。[F。莫拉莱斯、T. Bredtmann、S. Patchkovskii、J. Phys。乙：在。摩尔。选择。物理。49, 245001 (2016)] 通过注意到波函数从激光脉冲末端到无穷远的传播可以在一个步骤中非常有效地进行。在这项工作中，我们引入了 QPROP 3.0，其中添加了这种单步后传播（称为 i-SURFV）。讨论了说明新功能的示例。还解释了其他一些改进，主要涉及参数文件。其中添加了这种单步后传播（称为 i-SURFV）。讨论了说明新功能的示例。还解释了其他一些改进，主要涉及参数文件。其中添加了这种单步后传播（称为 i-SURFV）。讨论了说明新功能的示例。还解释了其他一些改进，主要涉及参数文件。