<div dir="ltr"><div><div><div><div><div><div><div>Dear Sir, <br></div>I want to calculate the ionization values of Diacetylene using MRCI. <br></div><div>To define the degeneracy I am using ref keyword. But my values are not accurate, even I have tried with different active space. The ionizations getting from OVGF (using gaussin03) seems better than the MRCI data.<br>
</div><div>Here I am giving the methods and results in eV.<br><br></div><div>method      IP1/IP2 (degenerate)    IP3/IP4 (degenerate)            IP5<br></div><div>OVGF           10.105                           12.623                              17.332<br>
</div><div>MRCI(8,8)     10.010                           12.584                              24.279  <br>
</div>MRCI(12,10)  10.006                           12.600                              18.299<br>MRCI(10,9)    10.040                           12.632                              18.2992 <br>MRCI(12,11)  10.009                           12.602                              18.183  <br>
</div><div> experiment    10.17                            12.62                                 16.61<br><br></div><div>First two IPs are in good agreement with experiment. Why I am getting large variation in case of IP5. Please suggest me to improve the IP5 value with experiment. <br>
</div><br></div>Here I am giving my MRCI (8,8) input file for better understanding<br><br> ***,coupling constants<br> memory,400,m<br> basis,avtz<br> geomtyp = xyz<br> geometry = {6,<br> planar isomer<br> C                     0.000000    0.000000    1.904717<br>
 C                     0.000000    0.000000    0.684532<br> H                     0.000000    0.000000    2.967194<br> C                     0.000000    0.000000   -0.684532<br> C                     0.000000    0.000000   -1.904717<br>
 H                     0.000000    0.000000   -2.967194<br> end}<br> {rhf;occ,5,1,1,0,4,1,1,0;wf,26,1,0;}<br> {multi;occ,6,2,2,0,5,1,1,0;closed,5,0,0,0,4,0,0,0;wf,26,1,0;}<br> {mrci;occ,6,2,2,0,5,1,1,0;closed,5,0,0,0,4,0,0,0;wf,26,1,0;}<br>
 {mrci;occ,6,2,2,0,5,1,1,0;closed,5,0,0,0,4,0,0,0;wf,25,2,1;ref,3;}<br> {mrci;occ,6,2,2,0,5,1,1,0;closed,5,0,0,0,4,0,0,0;wf,25,3,1;ref,2;}<br> {mrci;occ,6,2,2,0,5,1,1,0;closed,5,0,0,0,4,0,0,0;wf,25,6,1;ref,7;}<br> {mrci;occ,6,2,2,0,5,1,1,0;closed,5,0,0,0,4,0,0,0;wf,25,7,1;ref,6;}<br>
 {mrci;occ,6,2,2,0,5,1,1,0;closed,5,0,0,0,4,0,0,0;wf,25,1,1;state,2;}<br><br><br></div>Please suggest me to improve the ionization numbers.<br></div>Thank you in advance <br></div>Nagaprasad Reddy.<br><div><div><div><br><br>
<br></div></div></div></div>