Consider the following Schr(o|¨)dinger system:whoreλj,μj>0, j = 1.2.β>0. n = 2.3.In this paper, we study the existence of nontrivial radial ground states of the upper system by the Morse theory. A result from [Sirakov. Comm. Math. Phys, 271(2007). 199-221] is improved when proper restraint onλ1 andλ2 is given. |