Unless you can physically show these atheists Allah - they will never beleive you - no matter how many verbal acrobatics you perform for them. If Allah wanted to prove His existance to them, surelyn He could, yet he remains hidden to them because they have turned their backs on Him. Think about this - have you ever heard a non-Muslim pronounce the name of Allah? they usually pronounce it as "AAla" - In His infinite wisdom he has even deprived them of the virtue of simply saying his Beloved Isma. Before these atheistic kuffar can even begin to heal their hearts,they must first open their hearts up to the possibility of Supreme Inteligent Creator - and most refuse to do so.