<div dir="ltr">Dear David<div><br></div><div><span style="font-size:11.0pt;line-height:107%;font-family:"Calibri","sans-serif";color:black">Thank
you very much for  answer my question.</span><br></div><div><span style="font-size:11.0pt;line-height:107%;font-family:"Calibri","sans-serif";color:black"><br></span></div><div><font color="#000000" face="Calibri, sans-serif"><span style="font-size:14.6666669845581px;line-height:15.6933336257935px">First</span><span style="font-size:11pt;line-height:107%"> I vc-relax the pure surface (obtain a b c) and then </span><span style="font-size:14.6666669845581px;line-height:15.6933336257935px">different</span><span style="font-size:11pt;line-height:107%"> </span><span style="font-size:14.6666669845581px;line-height:15.6933336257935px">molecules</span><span style="font-size:11pt;line-height:107%"> </span><span style="font-size:14.6666669845581px;line-height:15.6933336257935px">adsorb</span><span style="font-size:11pt;line-height:107%"> on surface do vc-relax (a b c) a </span><span style="font-size:14.6666669845581px;line-height:15.6933336257935px">slightly</span><span style="font-size:11pt;line-height:107%"> changed.</span></font></div><div><span style="font-size:11.0pt;line-height:107%;font-family:"Calibri","sans-serif";color:black"><br></span></div><div><font color="#000000" face="Calibri, sans-serif"><span style="font-size:11pt;line-height:107%">for comparison </span><span style="font-size:14.6666669845581px;line-height:15.6933336257935px">result</span><span style="font-size:11pt;line-height:107%"> It is problem?</span></font></div><div><span style="font-size:11.0pt;line-height:107%;font-family:"Calibri","sans-serif";color:black"> </span></div><div><span style="font-size:11.0pt;line-height:107%;font-family:"Calibri","sans-serif";color:black">Best Regards</span></div><div><span style="font-size:11.0pt;line-height:107%;font-family:"Calibri","sans-serif";color:black">Elham</span></div><div><span style="font-size:12.8000001907349px">Ph.D. Student of Chemistry</span><span style="font-size:11.0pt;line-height:107%;font-family:"Calibri","sans-serif";color:black"><br></span></div></div>