<div dir="ltr">Dear users<div><br></div><div><br></div><div>I am calculating CBS PES of O2H+ ion. When I calculate a single point calculation of X-state keeping the distance between OH+ fragment and O-atom at 50 Ang at CAS/cc-pVQZ level, I get the following energy at CAS level E_cas = -149.8371634 hartrees.</div><div><br></div><div>Now, I do the individual calculation at the same level of the OH+ ion and O-atom seperately and I get E_cas(OH+) = -75.02897195 hartrees and E_cas(O) = -74.80987715 hartrees. When I sum, I get E_cas(OH+ and O) = -149.83884910 hartrees. I find that the summed energy and energy of the O2H+ ion calculated at 50 Ang differ by 0.0016857 hartrees which is sizable according to my opinion. </div><div><br></div><div>My question is that if there is any way out to reduce this difference to almost zero hartrees (i.e to say about 0.000001 hartrees)</div><div><br></div><div>I write below input file I used for each of the above mentioned calculation for the users to find out the possible mistakes in them if any</div><div><br></div><div>I will be happy to receive any comments from the experienced users to this issue.</div><div><br></div><div>Input file for O2H+ ion at 50 Ang</div><div>-----------------------------------------------</div><span style="font-family:monospace"><span style="color:rgb(0,0,0)"> ***,o2hp
</span><br> print,orbitals,civector
<br> !file,1,<a href="http://o2hp_ci_cs_2_1_titan.int">o2hp_ci_cs_2_1_titan.int</a>
<br> file,2,b.wfu
<br> !symmetry,x
<br>
<br> rcm=[1.258030346,0.9,1,1.1,1.15,1.2,1.25,1.3,1.35,1.4,1.5,1.6,1.7,1.8,1.9,2.0,2.05,2.1,2.2,2.3,2.4,2.6,2.8,\
<br> 3,3.2,3.4,3.6,3.8,4,4.5,5,6,8,10,15,20,30,50] ANG
<br>
<br> roh=1.008682076 ANG
<br> theta=30 DEGREE
<br>
<br> basis=cc-pVQZ
<br>
<br> do i=1,#rcm
<br>
<br> ro=rcm(i)
<br>
<br> symmetry,x
<br> geometry={ !geometry specification, using z-matrix
<br> 3
<br> O2HP
<br> O 0 0 -(1/17)*roh
<br> H 0 0 (16/17)*roh
<br> O 0 ro*sin(theta) ro*cos(theta)
<br> }
<br>
<br>
<br> {multi;config;wf,16,2,2;state,5;dm}
<br> emulti_gs(i)=energy(1)
<br> emulti_1xs(i)=energy(2)
<br> emulti_2xs(i)=energy(3)
<br> emulti_3xs(i)=energy(4)
<br> emulti_4xs(i)=energy(5)
<br> {ci;option,maxiti=5000;wf,16,2,2;state,5}
<br> eci_gs(i)=energy(1)
<br> eci_1xs(i)=energy(2)
<br> eci_2xs(i)=energy(3)
<br> eci_3xs(i)=energy(4)
<br> eci_4xs(i)=energy(5)<br></span><span style="font-family:monospace"><span style="color:rgb(0,0,0)"><br></span></span><div><span style="font-family:monospace"><span style="color:rgb(0,0,0)">table,rcm,emulti_gs,emulti_1xs,emulti_2xs,emulti_3xs,emulti_4xs
</span><br> Title,Results for O2H+
<br> table,rcm,eci_gs,eci_1xs,eci_2xs,eci_3xs,eci_4xs
<br>
<br> end do
<br>
<br> {pop;individual;density,2140.2,charge,state=1.2}
<br> {pop;individual;density,2140.2,charge,state=2.2}
<br> {pop;individual;density,2140.2,charge,state=3.2}
<br> {pop;individual;density,2140.2,charge,state=4.2}
<br> {pop;individual;density,2140.2,charge,state=5.2}<br>
<br></span><div> Input file for OH+ fragment</div><div>-------------------------------------------</div><div><span style="font-family:monospace"><span style="color:rgb(175,95,0)">***</span><span style="color:rgb(0,0,0)">,o2h</span><span style="color:rgb(175,95,0)">+</span><span style="color:rgb(0,0,0)">
</span><br><span style="color:rgb(175,95,0)">print</span><span style="color:rgb(0,0,0)">,orbitals,civector
</span><br>file,<span style="color:rgb(178,24,24)">1</span><span style="color:rgb(0,0,0)">,oh</span><span style="color:rgb(175,95,0)">+</span><span style="color:rgb(0,0,0)">_ci_c2v_4_1_mar5</span><span style="color:rgb(178,24,178)">.</span><span style="color:rgb(0,0,0)">int
</span><br>file,<span style="color:rgb(178,24,24)">2</span><span style="color:rgb(0,0,0)">,oh</span><span style="color:rgb(175,95,0)">+</span><span style="color:rgb(0,0,0)">_ci_c2v_4_1_mar5</span><span style="color:rgb(178,24,178)">.</span><span style="color:rgb(0,0,0)">wfu
</span><br>
<br>!rcm<span style="color:rgb(175,95,0)">=</span><span style="color:rgb(178,24,178)">[</span><span style="color:rgb(178,24,24)">1</span><span style="color:rgb(178,24,178)">.</span><span style="color:rgb(178,24,24)">0275782448</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(178,24,24)">0</span><span style="color:rgb(178,24,178)">.</span><span style="color:rgb(178,24,24)">5</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(178,24,24)">0</span><span style="color:rgb(178,24,178)">.</span><span style="color:rgb(178,24,24)">55</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(178,24,24)">0</span><span style="color:rgb(178,24,178)">.</span><span style="color:rgb(178,24,24)">6</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(178,24,24)">0</span><span style="color:rgb(178,24,178)">.</span><span style="color:rgb(178,24,24)">65</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(178,24,24)">0</span><span style="color:rgb(178,24,178)">.</span><span style="color:rgb(178,24,24)">7</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(178,24,24)">0</span><span style="color:rgb(178,24,178)">.</span><span style="color:rgb(178,24,24)">75</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(178,24,24)">0</span><span style="color:rgb(178,24,178)">.</span><span style="color:rgb(178,24,24)">8</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(178,24,24)">0</span><span style="color:rgb(178,24,178)">.</span><span style="color:rgb(178,24,24)">85</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(178,24,24)">0</span><span style="color:rgb(178,24,178)">.</span><span style="color:rgb(178,24,24)">9</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(178,24,24)">0</span><span style="color:rgb(178,24,178)">.</span><span style="color:rgb(178,24,24)">925</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(178,24,24)">0</span><span style="color:rgb(178,24,178)">.</span><span style="color:rgb(178,24,24)">95</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(178,24,24)">0</span><span style="color:rgb(178,24,178)">.</span><span style="color:rgb(178,24,24)">975</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(178,24,24)">1</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(178,24,24)">1</span><span style="color:rgb(178,24,178)">.</span><span style="color:rgb(178,24,24)">025</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(178,24,24)">1</span><span style="color:rgb(178,24,178)">.</span><span style="color:rgb(178,24,24)">05</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(178,24,24)">1</span><span style="color:rgb(178,24,178)">.</span><span style="color:rgb(178,24,24)">075</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(178,24,24)">1</span><span style="color:rgb(178,24,178)">.</span><span style="color:rgb(178,24,24)">1</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(178,24,24)">1</span><span style="color:rgb(178,24,178)">.</span><span style="color:rgb(178,24,24)">15</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(178,24,24)">1</span><span style="color:rgb(178,24,178)">.</span><span style="color:rgb(178,24,24)">2</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(178,24,24)">1</span><span style="color:rgb(178,24,178)">.</span><span style="color:rgb(178,24,24)">4</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(178,24,24)">1</span><span style="color:rgb(178,24,178)">.</span><span style="color:rgb(178,24,24)">6</span><span style="color:rgb(0,0,0)">,\
</span><br>! <span style="color:rgb(178,24,24)">1</span><span style="color:rgb(178,24,178)">.</span><span style="color:rgb(178,24,24)">8</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(178,24,24)">2</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(178,24,24)">2</span><span style="color:rgb(178,24,178)">.</span><span style="color:rgb(178,24,24)">5</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(178,24,24)">3</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(178,24,24)">3</span><span style="color:rgb(178,24,178)">.</span><span style="color:rgb(178,24,24)">5</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(178,24,24)">4</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(178,24,24)">4</span><span style="color:rgb(178,24,178)">.</span><span style="color:rgb(178,24,24)">5</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(178,24,24)">5</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(178,24,24)">6</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(178,24,24)">8</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(178,24,24)">10</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(178,24,24)">12</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(178,24,24)">14</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(178,24,24)">16</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(178,24,24)">18</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(178,24,24)">20</span><span style="color:rgb(178,24,178)">]</span><span style="color:rgb(0,0,0)"> ANG
</span><br>rcm<span style="color:rgb(175,95,0)">=</span><span style="color:rgb(178,24,178)">[</span><span style="color:rgb(178,24,24)">1</span><span style="color:rgb(178,24,178)">.</span><span style="color:rgb(178,24,24)">008682076</span><span style="color:rgb(178,24,178)">]</span><span style="color:rgb(0,0,0)"> ANG
</span><br>
<br>geometry<span style="color:rgb(175,95,0)">=</span><span style="color:rgb(0,0,0)">{ !geometry specification, using z-matrix
</span><br>o
<br>h o roh
<br>}
<br>
<br>basis<span style="color:rgb(175,95,0)">=cc</span><span style="color:rgb(0,0,0)">-pVQZ
</span><br>
<br>do i<span style="color:rgb(175,95,0)">=</span><span style="color:rgb(178,24,24)">1</span><span style="color:rgb(0,0,0)">,#rcm
</span><br>
<br>roh<span style="color:rgb(175,95,0)">=</span><span style="color:rgb(0,0,0)">rcm</span><span style="color:rgb(178,24,178)">(</span><span style="color:rgb(0,0,0)">i</span><span style="color:rgb(178,24,178)">)</span><span style="color:rgb(0,0,0)">
</span><br>
<br>{multi<span style="color:rgb(178,24,178)">;</span><span style="color:rgb(0,0,0)">config</span><span style="color:rgb(178,24,178)">;</span><span style="color:rgb(0,0,0)">wf,</span><span style="color:rgb(178,24,24)">8</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(178,24,24)">4</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(178,24,24)">2</span><span style="color:rgb(178,24,178)">;</span><span style="color:rgb(0,0,0)">dm}
</span><br>emulti_gs<span style="color:rgb(178,24,178)">(</span><span style="color:rgb(0,0,0)">i</span><span style="color:rgb(178,24,178)">)</span><span style="color:rgb(175,95,0)">=</span><span style="color:rgb(0,0,0)">energy</span><span style="color:rgb(178,24,178)">(</span><span style="color:rgb(178,24,24)">1</span><span style="color:rgb(178,24,178)">)</span><span style="color:rgb(0,0,0)">
</span><br>ci
<br>eci_gs<span style="color:rgb(178,24,178)">(</span><span style="color:rgb(0,0,0)">i</span><span style="color:rgb(178,24,178)">)</span><span style="color:rgb(175,95,0)">=</span><span style="color:rgb(0,0,0)">energy</span><span style="color:rgb(178,24,178)">(</span><span style="color:rgb(178,24,24)">1</span><span style="color:rgb(178,24,178)">)</span><span style="color:rgb(0,0,0)">
</span><br>eci_gs_david<span style="color:rgb(178,24,178)">(</span><span style="color:rgb(0,0,0)">i</span><span style="color:rgb(178,24,178)">)</span><span style="color:rgb(175,95,0)">=</span><span style="color:rgb(0,0,0)">energd</span><span style="color:rgb(178,24,178)">(</span><span style="color:rgb(178,24,24)">1</span><span style="color:rgb(178,24,178)">)</span><span style="color:rgb(0,0,0)">
</span><br>
<br><span style="color:rgb(175,95,0)">end</span><span style="color:rgb(0,0,0)"> do
</span><br>
<br>table,rcm,emulti_gs,eci_gs,eci_gs_david
<br>Title,Results <span style="color:rgb(175,95,0)">for</span><span style="color:rgb(0,0,0)"> OH</span><span style="color:rgb(175,95,0)">+</span><span style="color:rgb(0,0,0)"> dissociation </span><span style="color:rgb(178,24,24)">3</span><span style="color:rgb(0,0,0)">Sig- state
</span><br>
<br>{pop<span style="color:rgb(178,24,178)">;</span><span style="color:rgb(0,0,0)">individual</span><span style="color:rgb(178,24,178)">;</span><span style="color:rgb(0,0,0)">density,</span><span style="color:rgb(178,24,24)">2140</span><span style="color:rgb(178,24,178)">.</span><span style="color:rgb(178,24,24)">2</span><span style="color:rgb(0,0,0)">,charge,state</span><span style="color:rgb(175,95,0)">=</span><span style="color:rgb(178,24,24)">1</span><span style="color:rgb(178,24,178)">.</span><span style="color:rgb(178,24,24)">4</span><span style="color:rgb(0,0,0)">}</span><br>
<br></span></div><div>Input file for O-atom</div></div><div>----------------------------------</div><div><span style="font-family:monospace"><span style="color:rgb(175,95,0)">***</span><span style="color:rgb(0,0,0)">,o
</span><br><span style="color:rgb(175,95,0)">print</span><span style="color:rgb(0,0,0)">,orbitals,civector
</span><br>
<br>geometry<span style="color:rgb(175,95,0)">=</span><span style="color:rgb(0,0,0)">{ !geometry specification, using z-matrix
</span><br>o
<br>}
<br>
<br>basis<span style="color:rgb(175,95,0)">=cc</span><span style="color:rgb(0,0,0)">-pVQZ
</span><br>
<br>
<br>{multi<span style="color:rgb(178,24,178)">;</span><span style="color:rgb(0,0,0)">wf,</span><span style="color:rgb(178,24,24)">8</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(178,24,24)">4</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(178,24,24)">2</span><span style="color:rgb(178,24,178)">;</span><span style="color:rgb(0,0,0)">dm}
</span><br>ci<br>
<br></span></div></div>