Global phenomenological and microscopic optical model potentials for alpha Hairui Guo, Xinwu Su, Haiying Liang, Yongli Xu, Yinlu Han and Qingbiao Shen EPJ Web Conf., 146 (2017) 12011 Published online: 13 September 2017 DOI: 10.1051/epjconf/201714612011