The result of NRT calculation

The result of NRT calculation

Postby sunq188 » Tue Dec 18, 2018 10:04 am

It's a normal end of NRT calculation, but the result is unreliable. Here are my inputs and some important outputs.
$GENNBO NATOMS=114 NBAS=712 UPPER BODM $END
$NBO NRT NRTLST=1 NRTRES=70000 NRTOUT MEMORY=40gb NRTE2=30 $END
$COORD
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    Parent structure threshold:  50% of leading weight
 Delocalization list threshold:  30 kcal/mol
         Maximum search cycles:  3

 C1 symmetry, 1 symmetry operator(s), 1 unique atom permutation(s)
 128 initial TOPO matrices: NLS = 1; NBI = 127; SYM = 0

  cycle  structures    D(w)     kmax  CHOOSE   ION    E2   SYM   dbmax   dbrms
 ------------------------------------------------------------------------------
    1     128/128   0.10979161   128     128     0   768     0   2.000   1.248
    2     410/896   0.10738689   549    2304     0  2688     0   0.245   0.047
    3     880/3456  0.10562228  1355   20608  -384  4288     0   0.286   0.047

 QPNRT(880/3456): D(0)=0.13464383; D(w)=0.10562228; dbmax=0.286; dbrms=0.047
 Timing(sec): search=2485.32; Gram matrix=5495.38; minimize=3243.12; other=7373.74

       Resonance
    RS   Weight(%)                  Added(Removed)
 ---------------------------------------------------------------------------
     1      0.28
     2      0.28    C  1- C  4, ( C  1- O 22), ( C  2- C  3),  C  2- C  6,
                    C  3- O 21, ( C  4- C  5),  C  5- N 23, ( C  6- N 24),
                   ( O 21),  O 22, ( N 23),  N 24
     3      0.28   ( C 35- C 36),  C 35- C 37,  C 36- C 38, ( C 37- C 40),
                   ( C 38- C 42),  C 40- C 42


The weight of the leading resonance structure is only 0.28%. What' more, cycle 1 generates 128 structures, is it one in cycle 1?(In my opinion,it should be one because the initial structure is only one.(RDFT/RHF)) Thank you very much
sunq188
 
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Re: The result of NRT calculation

Postby ericg » Mon Jan 21, 2019 3:09 pm

I'm not sure what molecule you're performing NRT on, but it must be strongly delocalized for NRT to begin with 128 candidate structures (one from NBO analysis and 127 more from a search of the natural binding indices). That the leading weight is only 0.28% doesn't seem surprising to me.

I suspect that NRT is fine here, but I'd need more information from you if you really believe that the result is not reliable.

Eric
ericg
 
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