A globally accurate potential energy surface of $$\mathrm{HS_2}{(A\,^2A^\prime )}$$HS2(A2A′) and studies on the reaction dynamic of $$\mathrm{H}(^2\mathrm{S})+\mathrm{S_2}(a\,^1{\varDelta }_g)$$H(2S)+S2(a1Δg)