<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)Â Â Â Â 10.010Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 12.584Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 24.279Â <br>
</div>MRCI(12,10)Â 10.006 Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 12.600 Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 18.299<br>MRCI(10,9)Â Â Â 10.040Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 12.632 Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 18.2992 <br>MRCI(12,11)Â 10.009 Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 12.602 Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 18.183Â <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>Â ***,coupling constants<br>Â memory,400,m<br>Â basis,avtz<br>Â geomtyp = xyz<br>Â geometry = {6,<br>Â planar isomer<br>Â CÂ Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 0.000000Â Â Â 0.000000Â Â Â 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>
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