Latinus geminus

I think that Latin geminus and Skt. yama'- reflects a PIE g'em-

But I saw that Mattasovic (and not only) linked these forms with PIE
*yem-(o-no) > OIr. emon

On the other hand I know that PIE *y- (yekwr-) > Latin i-/j- (/iekur/)

So I'm confused here.

Thanks for help,
Marius