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Superconducting properties were studied on high quality superconductors$Ba_{x}(NH_{3})Fe_{2}Se_{2}$ ($T_{c}$ = 39 K) and $Sr_{x}(NH_{3})Fe_{2}Se_{2}$($T_{c}$ = 44 K) prepared by intercalating Ba/Sr atoms into tetragonal$\beta$-FeSe by liquid ammonia. The elongated c-axis and almost unchangeda-axis of $Ba_{x}(NH_{3})Fe_{2}Se_{2}$, comparing with $\beta$-FeSe, suggestedan unchanged intra-$Fe_{2}Se_{2}$-layer structure and the $T_{c}$ enhancementis due to a 3D to 2D-like Fermi surface transformation. The superconductingcoherent lengths $\xi$(0), Ginzburg-Landau parameters $\kappa$ and penetrationdepths $\lambda$(0) obtained from the extrapolated lower and upper criticalfields $B_{c1}$(0) and $B_{c2}$(0) indicates that both compounds are typicaltype-II superconductors. The temperature dependence of 1/$\lambda^{2}$(T) of$Ba_{x}(NH_{3})Fe_{2}Se_{2}$ deduced from the low field magnetic susceptibilityshows a two-gap s-wave behaviour with superconducting gaps of $\Delta_{1}$ =6.47 meV and $\Delta_{2}$ = 1.06 meV.

Two-gap superconducting properties of alkaline-earth intercalated $A_{x}(NH_{3})Fe_{2}Se_{2}$ (A = Ba or Sr)