On July 10th, Prof. Conrad A. P. Goodwin from the University of Manchester was invited by Prof. Zhang and Prof. Huang Wenliang to PKU for visit. In the morning, Prof. Zhang invited him to visit our group and take a photo. In afternoon, he gave a presentation titled "Valence Electron Configurational Isomerismand Low Oxidation States in the f-block" at A717. Conrad A. P. Goodwin is currently working in the Department of Chemistry at the University of Manchester, UK,  and his research focuses on Low-oxidation state lanthanide chemistry. Thank you Prof.  Conrad A. P. Goodwin for your visit!