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IV.A.4. (XIV.F.)

Relative enthalpies of isomers - Comparison of 0K enthalpies (kJ mol-1)

Isomers of CHNO

index Species CAS number Name Relative experimental enthalpy (kJ mol-1) sketch
a HNCO 75138 Isocyanic acid 0.0 sketch of Isocyanic acid
b HOCN 420053 cyanic acid   sketch of cyanic acid
c HCNO 506854 fulminic acid   sketch of fulminic acid
The calculated enthalpies include the calculated and scaled vibrational zero-point energy.
Methods with predefined basis sets
composite G1 0.0 a
105.6 b
292.2 c
G2MP2 0.0 a
109.5 b
292.0 c
G2 0.0 a
108.3 b
293.2 c
G3 0.0 a
107.4 b
291.2 c
G3MP2 0.0 a
106.9 b
292.3 c
CBS-Q 0.0 a
109.6 b
292.2 c

Methods with standard basis sets
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) 6-311+G(3df,2p) TZVP cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ cc-pV(T+d)Z
hartree fock HF 0.0 a
-20.0 b
289.2 c
0.0 a
85.7 b
349.4 c
0.0 a
85.7 b
349.4 c
0.0 a
86.2 b
326.2 c
  0.0 a
99.5 b
350.4 c
0.0 a
98.7 b
347.1 c
0.0 a
110.3 b
352.5 c
0.0 a
101.7 b
355.9 c
0.0 a
104.7 b
351.5 c
0.0 a
105.6 b
351.9 c
0.0 a
98.4 b
349.0 c
0.0 a
101.9 b
351.6 c
0.0 a
103.3 b
350.5 c
0.0 a
103.9 b
350.7 c
0.0 a
102.7 b
351.5 c
0.0 a
103.6 b
349.6 c
0.0 a
103.3 b
350.5 c
density functional LSDA 0.0 a
86.9 b
224.2 c
0.0 a
138.4 b
268.5 c
0.0 a
138.4 b
268.5 c
0.0 a
138.2 b
248.0 c
0.0 a
135.8 b
246.7 c
0.0 a
131.1 b
250.7 c
0.0 a
128.9 b
252.9 c
0.0 a
142.9 b
257.6 c
0.0 a
134.6 b
260.6 c
0.0 a
133.4 b
253.5 c
    0.0 a
131.3 b
248.0 c
0.0 a
132.2 b
256.0 c
  0.0 a
129.5 b
256.5 c
  0.0 a
132.2 b
256.0 c
SVWN   0.0 a
138.4 b
268.5 c
    0.0 a
135.8 b
245.2 c
  0.0 a
128.9 b
252.9 c
                     
BLYP 0.0 a
69.0 b
223.5 c
0.0 a
120.6 b
262.3 c
0.0 a
120.6 b
262.3 c
0.0 a
122.6 b
243.3 c
0.0 a
126.3 b
253.9 c
0.0 a
121.7 b
258.4 c
0.0 a
119.8 b
259.2 c
0.0 a
131.6 b
262.9 c
0.0 a
124.2 b
265.3 c
0.0 a
123.8 b
260.8 c
               
B1B95 0.0 a
53.7 b
246.8 c
0.0 a
116.3 b
289.8 c
0.0 a
116.3 b
289.8 c
0.0 a
116.8 b
267.7 c
0.0 a
111.8 b
264.0 c
0.0 a
117.7 b
279.8 c
0.0 a
116.1 b
279.5 c
0.0 a
128.3 b
283.3 c
0.0 a
120.2 b
286.7 c
      0.0 a
118.3 b
277.3 c
0.0 a
108.1 b
271.4 c
      0.0 a
108.1 b
271.4 c
B3LYP 0.0 a
53.2 b
244.7 c
0.0 a
115.2 b
284.5 c
0.0 a
115.2 b
284.5 c
0.0 a
116.7 b
264.6 c
0.0 a
122.4 b
274.6 c
0.0 a
117.5 b
279.4 c
0.0 a
116.0 b
279.6 c
0.0 a
127.9 b
283.1 c
0.0 a
120.0 b
286.2 c
0.0 a
120.3 b
280.3 c
  0.0 a
118.8 b
283.2 c
0.0 a
117.5 b
275.2 c
0.0 a
119.5 b
283.9 c
  0.0 a
117.0 b
282.5 c
0.0 a
119.4 b
283.8 c
0.0 a
119.5 b
283.9 c
B3LYPultrafine         0.0 a
122.4 b
274.6 c
  0.0 a
116.0 b
            0.0 a
119.5 b
       
B3PW91 0.0 a
58.3 b
245.3 c
0.0 a
119.4 b
288.5 c
0.0 a
119.4 b
288.5 c
0.0 a
119.7 b
266.4 c
0.0 a
125.6 b
273.2 c
0.0 a
120.6 b
278.1 c
0.0 a
119.0 b
277.8 c
0.0 a
131.7 b
281.8 c
0.0 a
123.4 b
285.2 c
0.0 a
122.9 b
279.0 c
    0.0 a
121.4 b
275.0 c
0.0 a
122.4 b
281.5 c
      0.0 a
122.4 b
281.5 c
mPW1PW91 0.0 a
54.0 b
250.3 c
0.0 a
114.4 b
290.8 c
0.0 a
117.7 b
293.9 c
0.0 a
118.0 b
271.1 c
0.0 a
121.7 b
274.9 c
0.0 a
116.6 b
279.9 c
0.0 a
115.2 b
279.5 c
0.0 a
127.9 b
283.7 c
0.0 a
122.4 b
289.9 c
0.0 a
122.0 b
284.1 c
    0.0 a
117.6 b
277.5 c
0.0 a
118.6 b
283.0 c
      0.0 a
118.6 b
283.0 c
M06-2X         0.0 a
106.4 b
286.9 c
                         
PBEPBE 0.0 a
76.6 b
225.1 c
0.0 a
125.9 b
265.9 c
0.0 a
125.9 b
265.9 c
0.0 a
127.3 b
244.9 c
0.0 a
130.8 b
250.6 c
0.0 a
126.0 b
255.3 c
0.0 a
124.0 b
255.7 c
0.0 a
136.6 b
259.7 c
0.0 a
128.7 b
262.2 c
0.0 a
127.6 b
257.3 c
    0.0 a
126.5 b
252.3 c
0.0 a
126.9 b
260.3 c
    0.0 a
126.7 b
260.3 c
0.0 a
126.9 b
260.3 c
PBEPBEultrafine         0.0 a
130.8 b
                         
PBE1PBE         0.0 a
125.2 b
276.3 c
                         
HSEh1PBE         0.0 a
125.4 b
275.7 c
                         
TPSSh             0.0 a
119.9 b
268.8 c
                     
Moller Plesset perturbation MP2 0.0 a
-3.4 b
225.6 c
0.0 a
88.0 b
282.5 c
0.0 a
88.0 b
282.5 c
0.0 a
86.5 b
261.6 c
0.0 a
105.2 b
271.1 c
0.0 a
100.6 b
277.0 c
  0.0 a
112.7 b
276.0 c
0.0 a
101.0 b
281.9 c
0.0 a
106.4 b
278.0 c
  0.0 a
101.0 b
274.4 c
0.0 a
100.6 b
275.5 c
0.0 a
103.5 b
272.9 c
  0.0 a
102.8 b
278.8 c
  0.0 a
103.5 b
277.5 c
MP2=FULL
NC
NC
0.0 a
88.1 b
282.3 c
0.0 a
88.1 b
282.3 c
0.0 a
86.6 b
261.5 c
0.0 a
105.8 b
271.1 c
0.0 a
101.3 b
277.0 c
0.0 a
100.4 b
274.3 c
0.0 a
113.1 b
275.8 c
0.0 a
101.6 b
281.7 c

NC
NC
    0.0 a
101.1 b
275.4 c
0.0 a
105.6 b
270.3 c
      0.0 a
105.6 b
275.1 c
MP3=FULL         0.0 a
95.8 b
298.0 c
  0.0 a
90.9 b
301.6 c
                     
MP4                           0.0 a
107.4 b
       
B2PLYP         0.0 a
116.9 b
270.6 c
                0.0 a
114.0 b
278.7 c
       
Configuration interaction CID  
NC
NC

NC
NC

NC
NC

NC
NC
   
NC
NC
                   
CISD   0.0 a
81.7 b
303.0 c

NC
NC

NC
NC
0.0 a
102.8 b
306.7 c
   
NC
NC
                   
Quadratic configuration interaction QCISD
NC
NC
0.0 a
79.4 b
281.3 c
0.0 a
79.4 b
281.3 c
0.0 a
79.2 b
259.8 c
0.0 a
99.5 b
285.7 c
0.0 a
94.9 b
292.2 c
0.0 a
93.4 b
288.8 c
0.0 a
106.8 b
293.2 c
0.0 a
95.9 b
299.2 c

NC
NC
    0.0 a
96.1 b
293.9 c
0.0 a
98.6 b
296.7 c
      0.0 a
98.6 b
296.7 c
Coupled Cluster CCD
NC
NC
0.0 a
67.4 b
287.8 c
0.0 a
67.4 b
287.8 c
0.0 a
68.3 b
265.9 c
0.0 a
92.6 b
292.2 c
0.0 a
88.2 b
298.2 c
0.0 a
87.5 b
295.1 c
0.0 a
100.0 b
298.6 c

NC
NC

NC
NC
    0.0 a
89.0 b
297.0 c
0.0 a
93.5 b
      0.0 a
93.5 b
CCSD(T)         0.0 a
279.0 c
                         

Methods with effective core potentials (select basis sets)
CEP-31G CEP-31G* CEP-121G CEP-121G* LANL2DZ SDD
hartree fock HF 0.0 a
80.4 b
303.1 c
0.0 a
104.2 b
343.3 c
0.0 a
76.6 b
302.7 c
0.0 a
100.7 b
342.0 c
0.0 a
84.4 b
315.6 c
0.0 a
84.7 b
316.0 c
density functional B1B95 0.0 a
115.3 b
259.6 c
0.0 a
120.8 b
275.2 c
       
B3LYP 0.0 a
107.8 b
252.7 c
0.0 a
118.0 b
277.6 c
0.0 a
105.0 b
252.2 c
0.0 a
116.2 b
278.6 c
0.0 a
114.3 b
258.2 c
0.0 a
114.4 b
258.5 c
Moller Plesset perturbation MP2 0.0 a
78.0 b
249.8 c
0.0 a
103.1 b
275.0 c
0.0 a
75.2 b
249.5 c
0.0 a
101.0 b
273.7 c
0.0 a
82.2 b
254.5 c
0.0 a
82.0 b
254.7 c

Single point energy calculations (select basis sets)
6-311+G(3df,2p) cc-pVDZ cc-pVTZ aug-cc-pVDZ aug-cc-pVTZ cc-pV(T+d)Z
Moller Plesset perturbation MP2FC// HF/6-31G* 0.0 a
113.1 b
291.8 c
  0.0 a
108.8 b
291.8 c
    0.0 a
108.8 b
291.8 c
MP2FC// B3LYP/6-31G* 0.0 a
108.7 b
282.0 c
0.0 a
102.9 b
283.6 c
0.0 a
104.3 b
282.1 c
    0.0 a
104.3 b
282.1 c
MP2FC// MP2FC/6-31G*     0.0 a
102.9 b
278.1 c
0.0 a
102.0 b
279.1 c
0.0 a
104.5 b
277.8 c
0.0 a
102.9 b
278.1 c
MP4// HF/6-31G* 0.0 a
114.6 b
286.2 c
  0.0 a
22.5 b
198.6 c
    0.0 a
22.5 b
198.6 c
MP4// B3LYP/6-31G*   0.0 a
107.1 b
279.8 c
0.0 a
107.5 b
277.5 c
    0.0 a
107.5 b
277.5 c
MP4// MP2/6-31G*     0.0 a
106.5 b
272.4 c
    0.0 a
106.5 b
272.4 c
Coupled Cluster CCSD// B3LYP/6-31G* 0.0 a
99.1 b
299.8 c
         
CCSD(T)// B3LYP/6-31G* 0.0 a
103.8 b
289.4 c
  0.0 a
99.5 b
289.3 c
     
CCSD(T)//B3LYP/6-31G(2df,p)     0.0 a
100.1 b
287.7 c
    0.0 a
100.1 b
287.7 c
CCSD// MP2FC/6-31G*       0.0 a
92.7 b
302.6 c
0.0 a
96.6 b
305.1 c
 
CCSD(T)// MP2FC/6-31G*       0.0 a
96.9 b
289.2 c
0.0 a
100.4 b
289.6 c
 
NC = not calculated
For descriptions of the methods (AM1, HF, MP2, ...) and basis sets (3-21G, 3-21G*, 6-31G, ...) see the glossary in section I.C. Predefined means the basis set used is determined by the method.
gaw refers to the group additivity method implemeted in the NIST Chemistry Webbook.

See section III.C.1 List or set vibrational scaling factors to change the scale factors used here.
See section III.C.2 Calculate a vibrational scaling factor for a given set of molecules to determine the least squares best scaling factor.