<div dir="ltr">Hi all, <div>I want to calculate BSSE where one of the atoms has an ECP potential basis on it. Should BSSE be computed differently for ECP? There is some discussion in the literature about switching off the core but I am not sure how to do that in molpro. </div><div><br></div><div>As a test I compute BSSE for two noble gas atoms with AVDZ basis and get a BSSE of about 47 cm-1. Then I switch the basis on one of the atoms to be def2-SVPD and I get BSSE which is twice that of the AVDZ result (about 97 cm-1). </div><div><br></div><div>However, the CP corrected interaction energy is approximately the same between the two calculations. 400 cm-1 vs 403 cm-1, so maybe nothing special needs to be done. Can anyone please help clarify this for me.</div><div>Thanks</div><div>Amit</div><div><br></div><div><p style="margin:0px;line-height:normal"><span style="font-family:Menlo;font-size:13px;color:rgb(206,121,36)">***</span><span style="font-family:Menlo;font-size:13px">, Ar </span><span style="font-family:Menlo;font-size:13px;color:rgb(206,121,36)">+</span><font face="Menlo"> he bsse </font></p><p style="margin:0px;font-size:13px;line-height:normal;font-family:Menlo;min-height:15px"><span style=""></span><br></p><p style="margin:0px;font-size:13px;line-height:normal;font-family:Menlo"><span style="">geometry</span><span style="color:rgb(206,121,36)">=</span><span style="">{Ar</span></p><p style="margin:0px;font-size:13px;line-height:normal;font-family:Menlo"><span style="">He Ar Rx}</span></p><p style="margin:0px;font-size:13px;line-height:normal;font-family:Menlo;min-height:15px"><span style=""></span><br></p><p style="margin:0px;font-size:13px;line-height:normal;font-family:Menlo"><span style="">Rx</span><span style="color:rgb(206,121,36)">=5.0</span></p><p style="margin:0px;font-size:13px;line-height:normal;font-family:Menlo;min-height:15px"><span style=""></span><br></p><p style="margin:0px;font-size:13px;line-height:normal;font-family:Menlo"><span style="">!basis</span><span style="color:rgb(206,121,36)">=</span><span style="">avdz,he</span><span style="color:rgb(206,121,36)">=</span><span style="">avdz</span></p><p style="margin:0px;font-size:13px;line-height:normal;font-family:Menlo"><span style="">basis</span><span style="color:rgb(206,121,36)">=</span><span style="">def2-SVPD,he</span><span style="color:rgb(206,121,36)">=</span><span style="">avdz</span></p><p style="margin:0px;font-size:13px;line-height:normal;font-family:Menlo;min-height:15px"><span style=""></span><br></p><p style="margin:0px;font-size:13px;line-height:normal;font-family:Menlo;min-height:15px"><span style=""></span><br></p><p style="margin:0px;font-size:13px;line-height:normal;font-family:Menlo"><span style=""> text,calculation </span><span style="color:rgb(206,121,36)">for</span><span style=""> complex</span></p><p style="margin:0px;font-size:13px;line-height:normal;font-family:Menlo"><span style=""> hf                            !RHF </span><span style="color:rgb(206,121,36)">for</span><span style=""> total system</span></p><p style="margin:0px;font-size:13px;line-height:normal;font-family:Menlo"><span style=""> ccsd</span><span style="color:rgb(213,59,211)">(</span><span style="">t</span><span style="color:rgb(213,59,211)">)</span></p><p style="margin:0px;font-size:13px;line-height:normal;font-family:Menlo"><span style=""> e_Arhe</span><span style="color:rgb(206,121,36)">=</span><span style="">energy                 !save energy in variable e_Arhe</span></p><p style="margin:0px;font-size:13px;line-height:normal;font-family:Menlo;min-height:15px"><span style=""></span><br></p><p style="margin:0px;font-size:13px;line-height:normal;font-family:Menlo"><span style=""> text,cp calculation </span><span style="color:rgb(206,121,36)">for</span><span style=""> HE</span></p><p style="margin:0px;font-size:13px;line-height:normal;font-family:Menlo"><span style=""> dummy,Ar                      !make Ar a dummy</span></p><p style="margin:0px;font-size:13px;line-height:normal;font-family:Menlo"><span style=""> hf                           !RHF </span><span style="color:rgb(206,121,36)">for</span><span style=""> He</span></p><p style="margin:0px;font-size:13px;line-height:normal;font-family:Menlo"><span style=""> ccsd</span><span style="color:rgb(213,59,211)">(</span><span style="">t</span><span style="color:rgb(213,59,211)">)</span></p><p style="margin:0px;font-size:13px;line-height:normal;font-family:Menlo"><span style=""> e_he</span><span style="color:rgb(206,121,36)">=</span><span style="">energy                   !save energy in variable e_he</span></p><p style="margin:0px;font-size:13px;line-height:normal;font-family:Menlo;min-height:15px"><span style=""></span><br></p><p style="margin:0px;font-size:13px;line-height:normal;font-family:Menlo"><span style=""> text,cp calculation </span><span style="color:rgb(206,121,36)">for</span><span style=""> Ar</span></p><p style="margin:0px;font-size:13px;line-height:normal;font-family:Menlo"><span style=""> dummy,he                      !make he dummy</span></p><p style="margin:0px;font-size:13px;line-height:normal;font-family:Menlo"><span style=""> hf</span></p><p style="margin:0px;font-size:13px;line-height:normal;font-family:Menlo"><span style=""> ccsd</span><span style="color:rgb(213,59,211)">(</span><span style="">t</span><span style="color:rgb(213,59,211)">)</span></p><p style="margin:0px;font-size:13px;line-height:normal;font-family:Menlo"><span style=""> e_Ar</span><span style="color:rgb(206,121,36)">=</span><span style="">energy                   !save energy in variable e_Ar</span></p><p style="margin:0px;font-size:13px;line-height:normal;font-family:Menlo;min-height:15px"><span style=""></span><br></p><p style="margin:0px;font-size:13px;line-height:normal;font-family:Menlo"><span style=""> text,separate calculation </span><span style="color:rgb(206,121,36)">for</span><span style=""> he</span></p><p style="margin:0px;font-size:13px;line-height:normal;font-family:Menlo"><span style=""> symmetry,x,y</span></p><p style="margin:0px;font-size:13px;line-height:normal;font-family:Menlo"><span style=""> geometry</span><span style="color:rgb(206,121,36)">=</span><span style="">{he}                 !geometry </span><span style="color:rgb(206,121,36)">for</span><span style=""> he alone</span></p><p style="margin:0px;font-size:13px;line-height:normal;font-family:Menlo"><span style=""> hf                            !RHF </span><span style="color:rgb(206,121,36)">for</span><span style=""> He</span></p><p style="margin:0px;font-size:13px;line-height:normal;font-family:Menlo"><span style=""> ccsd</span><span style="color:rgb(213,59,211)">(</span><span style="">t</span><span style="color:rgb(213,59,211)">)</span></p><p style="margin:0px;font-size:13px;line-height:normal;font-family:Menlo"><span style=""> e_he_inf</span><span style="color:rgb(206,121,36)">=</span><span style="">energy               !save energy in variable e_he_inf</span></p><p style="margin:0px;font-size:13px;line-height:normal;font-family:Menlo;min-height:15px"><span style=""></span><br></p><p style="margin:0px;font-size:13px;line-height:normal;font-family:Menlo"><span style=""> text,separate calculation </span><span style="color:rgb(206,121,36)">for</span><span style=""> Ar</span></p><p style="margin:0px;font-size:13px;line-height:normal;font-family:Menlo"><span style=""> symmetry,x,y</span></p><p style="margin:0px;font-size:13px;line-height:normal;font-family:Menlo"><span style=""> geometry</span><span style="color:rgb(206,121,36)">=</span><span style="">{Ar}                 !geometry </span><span style="color:rgb(206,121,36)">for</span><span style=""> Ar alone</span></p><p style="margin:0px;font-size:13px;line-height:normal;font-family:Menlo"><span style=""> hf                            !scf </span><span style="color:rgb(206,121,36)">for</span><span style=""> Ar</span></p><p style="margin:0px;font-size:13px;line-height:normal;font-family:Menlo"><span style=""> ccsd</span><span style="color:rgb(213,59,211)">(</span><span style="">t</span><span style="color:rgb(213,59,211)">)</span></p><p style="margin:0px;font-size:13px;line-height:normal;font-family:Menlo"><span style=""> e_Ar_inf</span><span style="color:rgb(206,121,36)">=</span><span style="">energy               !save energy in variable e_Ar_inf</span></p><p style="margin:0px;font-size:13px;line-height:normal;font-family:Menlo;min-height:15px"><span style=""></span><br></p><p style="margin:0px;font-size:13px;line-height:normal;font-family:Menlo"><span style="">de</span><span style="color:rgb(213,59,211)">(</span><span style="">i</span><span style="color:rgb(213,59,211)">)</span><span style="color:rgb(206,121,36)">=</span><span style="color:rgb(213,59,211)">(</span><span style="">e_Arhe-e_he_inf-e_Ar_inf</span><span style="color:rgb(213,59,211)">)</span><span style="color:rgb(206,121,36)">*</span><span style="">tocm    !compute uncorrected interaction energy</span></p><p style="margin:0px;font-size:13px;line-height:normal;font-family:Menlo"><span style="">de_cp</span><span style="color:rgb(213,59,211)">(</span><span style="">i</span><span style="color:rgb(213,59,211)">)</span><span style="color:rgb(206,121,36)">=</span><span style="color:rgb(213,59,211)">(</span><span style="">e_Arhe-e_he-e_Ar</span><span style="color:rgb(213,59,211)">)</span><span style="color:rgb(206,121,36)">*</span><span style="">tocm         !compute counter-poise corrected interaction energy</span></p><p style="margin:0px;font-size:13px;line-height:normal;font-family:Menlo"><span style="">bsse_he</span><span style="color:rgb(213,59,211)">(</span><span style="">i</span><span style="color:rgb(213,59,211)">)</span><span style="color:rgb(206,121,36)">=</span><span style="color:rgb(213,59,211)">(</span><span style="">e_he-e_he_inf</span><span style="color:rgb(213,59,211)">)</span><span style="color:rgb(206,121,36)">*</span><span style="">tocm          !BSSE </span><span style="color:rgb(206,121,36)">for</span><span style=""> he</span></p><p style="margin:0px;font-size:13px;line-height:normal;font-family:Menlo"><span style="">bsse_Ar</span><span style="color:rgb(213,59,211)">(</span><span style="">i</span><span style="color:rgb(213,59,211)">)</span><span style="color:rgb(206,121,36)">=</span><span style="color:rgb(213,59,211)">(</span><span style="">e_Ar-e_Ar_inf</span><span style="color:rgb(213,59,211)">)</span><span style="color:rgb(206,121,36)">*</span><span style="">tocm          !BSSE </span><span style="color:rgb(206,121,36)">for</span><span style=""> Ar</span></p><p style="margin:0px;font-size:13px;line-height:normal;font-family:Menlo">




















































</p><p style="margin:0px;font-size:13px;line-height:normal;font-family:Menlo"><span style="">bsse_tot</span><span style="color:rgb(213,59,211)">(</span><span style="">i</span><span style="color:rgb(213,59,211)">)</span><span style="color:rgb(206,121,36)">=</span><span style="">bsse_he</span><span style="color:rgb(213,59,211)">(</span><span style="">i</span><span style="color:rgb(213,59,211)">)</span><span style="color:rgb(206,121,36)">+</span><span style="">bsse_Ar</span><span style="color:rgb(213,59,211)">(</span><span style="">i</span><span style="color:rgb(213,59,211)">)</span><span style="">              !total BSSE</span></p></div></div>