*Article* **Spectroscopic Peculiarities at Ionization of Excited <sup>2</sup>***p***<sup>5</sup>(<sup>2</sup>***PJf* **)<sup>3</sup>***s***[***K***]0,1,2 States of Ne: Cooper Minima and Autoionizing Resonances**

**Maria M. Popova 1,2, Maksim D. Kiselev 1,2,3, Sergei M. Burkov 4, Elena V. Gryzlova 2,\* and Alexei N. Grum-Grzhimailo 2,3**

	- Correspondence: gryzlovaev@depni.sinp.msu.ru; Tel.: +7-905-763-2237

**Abstract:** An extensive study of photoionization from neon excited states was performed. The R-matrix approach was applied to calculate a photoionization cross-section from the metastable <sup>2</sup>*p*<sup>5</sup>(<sup>2</sup>*PJf* )<sup>3</sup>*s*[*K*]0,2 and dipole-allowed <sup>2</sup>*p*<sup>5</sup>(<sup>2</sup>*PJf* )<sup>3</sup>*s*[*K*]1 states. The resonance structures and Cooper minimum accessible in photoionization from the excited states by the photons with energy below 30 eV were analyzed. The parameters of the lowest autoionizing states (AISs) of even parity were extracted by fitting of the photoionization cross-section. For the dipole-allowed states, calculations are presented for unpolarized, linearly and circularly polarized radiation.

**Keywords:** photoionization; neon; excited states; spectroscopy; Cooper minimum; electrons correlations; R-matrix; autoionizing state; metastable state
