10.6084/m9.figshare.1012429.v1 H Iwayama H Iwayama N Saito N Saito K Ueda K Ueda K Motomura K Motomura G Prümper G Prümper X-J Liu X-J Liu H Fukuzawa H Fukuzawa M Yao M Yao K Nagaya K Nagaya A Rudenko A Rudenko TOF spectra of Ar clusters (〈<em>N</em>〉 ~ 1000) at four different laser intensities: (a) 10%, (b) 15%, (c) 62% and (d) 100% of the maximum laser intensity IOP Publishing 2013 intensity euv Ar clusters results electron laser power dependence charge energy distributions Ar clusters tof ion momentum spectrometer Atomic Physics Molecular Physics 2013-08-13 00:00:00 Figure https://iop.figshare.com/articles/figure/_TOF_spectra_of_Ar_clusters_em_N_em_1000_at_four_different_laser_intensities_a_10_b_15_c_62_and_d_10/1012429 <p><strong>Figure 1.</strong> TOF spectra of Ar clusters (〈<em>N</em>〉 ~ 1000) at four different laser intensities: (a) 10%, (b) 15%, (c) 62% and (d) 100% of the maximum laser intensity. Background contributions are subtracted.</p> <p><strong>Abstract</strong></p> <p>We report on the laser power dependence of photoabsorptions of Ar clusters irradiated by extreme ultraviolet–free electron laser (EUV–FEL) at the wavelength of 62 nm. We measured kinetic energy distributions of fragment ions with our ion momentum spectrometer. From the measured kinetic energy distributions, we estimated charge states of irradiated Ar clusters using the classical uniformly charged sphere model. Our results show that the EUV–FEL irradiation of Ar clusters results in the frustration of direct photoionization leading to nanoplasma formation and subsequent strong electron–ion charge recombination.</p>