# Redundant out of plane bends in gaussian not recognised

I'm having an issue with something that shouldn't be that complicated. I'm trying to generate some surfaces with Gaussian to look at amine planarisations, but the modredundant command doesn't seem to be recognising the out-of-plane bend coordinate type, spitting out the error: "Unrecognised coordinate type "O"".

I've tried different coordinate types, they all work, but it seems this one specifically is not working. Does anybody have any ideas to help me? Code below:

%chk=MR-test.chk
# opt=modredundant tda=(nstates=6) cam-b3lyp/6-31++G(d,p) geom=connectivity

Amine planarisation test

0 1
N                  0.14115899    0.72065377    0.00000000
C                  0.63114217   -0.66528146    0.00000000
H                  1.70114039   -0.66529528    0.00195365
C                  0.62897198    1.41283584    1.20159164
H                  0.27231899    2.42164635    1.20159076
H                  0.27070141    0.90787342    2.07426291
H                  1.69897019    1.41282074    1.20354879
C                  0.63336050    1.41438736   -1.19890424
H                  0.27828574    0.91055325   -2.07353165
H                  0.27670608    2.42319736   -1.19890424
H                  1.70335872    1.41437379   -1.19694825
C                  0.12009706   -1.39042562   -1.25880851
H                  0.78378957   -1.19762146   -2.07565538
H                  0.08029786   -2.44332208   -1.07246188
H                 -0.85887294   -1.03416700   -1.50293458
C                  0.11550541   -1.39204895    1.25599672
H                  0.72562653   -1.13043658    2.09516963
H                 -0.89643994   -1.10106296    1.44624332
H                  0.15906269   -2.44960896    1.09924986

1 2 1.0 4 1.0 8 1.0
2 3 1.0 12 1.0 16 1.0
3
4 5 1.0 6 1.0 7 1.0
5
6
7
8 9 1.0 10 1.0 11 1.0
9
10
11
12 13 1.0 14 1.0 15 1.0
13
14
15
16 17 1.0 18 1.0 19 1.0
17
18
19

O 1 8 4 2 S 25 2.000000


I've tried generating the input both with GaussView and typing it myself. It really doesn't seem to like out-of-plane bends. Thanks in advance.

• I couldn't get this to run either. From looking at the mod redundant coordinate in Gaussview, I notice that it does not give a degree measure for the out of plane bend initially, so it doesn't seem to be measuring anything right from the start. – Tyberius Sep 11 '17 at 18:42

## 1 Answer

According to Gaussian's Modredund description, there is no such type as "O" anymore in Gaussian16. Hence, the input deck is rejected. Gaussian16 provides generalized internal coordinates, for which more complex expressions are possible.

• That's a little annoying, but thanks for the link to the generalised internal coordinates. :) – Max Sep 19 '17 at 12:57
• Maybe Gaussian has a canonical solution for you. I'd ask their helpdesk. I agree that it is ... unfortunate. – Deathbreath Sep 20 '17 at 16:53
• @Deathbreath I tried "O" in gaussian09 It just finished the job without error BUT it didn't give me any "scan" result. :/ – Baris Vvolf Jan 15 '19 at 5:13