<html><head></head><body><div style="color:#000; background-color:#fff; font-family:Courier New, courier, monaco, monospace, sans-serif;font-size:16px"><div dir="ltr" id="yui_3_16_0_1_1452505253007_12946">for LiF(001) surface how can I choose the convergence of slab<br></div></div></body></html>