Supporting Information
for the article
Numerical Study of the Superadiabatic Flame Temperature Phenomenon in HN3 Flame
by
*O.P. Korobeinicheva, A.A.Paletskya, T.A.Bolshovaa and V.DKnyazevb
aInstitute of Chemical Kinetics and Combustion SB RAS, Novosibirsk, Russia
bThe Catholic University of America, Washington, D. C., United States of America
Table 1S. Kinetics mechanism of HN3 decomposition
(k = A T**b exp(-E/RT)) A units: mole-cm-sec-K, E units Joules/mole
REACTIONS CONSIDERED A b E
1. N3H+N2=N2+NH+N2 2.14E+26 -3.0 195151.0
2. N3H+N3H=N2+NH+N3H 6.67E+26 -2.9 201280.0
3. N3H+AR=N2+NH+AR 7.55E+25 -3.0 191551.0
4. N3H+H=N2+NH2 3.71E+07 1.9 13754.0
5. N3H+N=N2+NNH 1.87E+08 1.5 14500.0
6. N3H+NH=NH2+N3 7.83E+02 3.2 41700.0
7. N3H+NH2=NH3+N3 5.88E+00 3.5 -2900.0
8. H+H+M=H2+M 6.50E+17 -1.0 0.0
H2 Enhanced by 0.000E+00
9. H+H+H2=H2+H2 1.00E+17 -0.6 0.0
10. N2+M=N+N+M 1.00E+28 -3.3 942030.0
N2 Enhanced by 5.000E+00
11. NH+M=N+H+M 2.65E+14 0.0 316100.0
12. NH+H=N+H2 3.20E+13 0.0 1360.0
13. NH+N=N2+H 9.00E+11 0.5 0.0
14. NH+NH=NH2+N 5.95E+02 2.9 -8370.0
15. NH+NH=N2+H2 1.00E+08 1.0 0.0
16. NH+NH=N2+H+H 2.54E+13 0.0 0.0
17. NH2+M=NH+H+M 3.16E+23 -2.0 382670.0
18. NH+H2=NH2+H 1.00E+14 0.0 84030.0
19. NH2+N=N2+H+H 6.90E+13 0.0 0.0
20. NH2+NH=N2H2+H 1.50E+15 -0.5 0.0
21. NH2+NH=NH3+N 1.00E+13 0.0 8370.0
22. NH3+NH=NH2+NH2 3.16E+14 0.0 112080.0
23. NH2+NH2=N2H2+H2 1.00E+13 0.0 6280.0
24. NH3+M=NH2+H+M 2.20E+16 0.0 391340.0
25. NH3+M=NH+H2+M 6.30E+14 0.0 391000.0
26. NH3+H=NH2+H2 5.42E+05 2.4 41530.0
27. NH3+NH2=N2H3+H2 1.00E+11 0.5 90430.0
28. NNH=N2+H 3.00E+08 0.0 0.0
29. NNH+M=N2+H+M 1.00E+13 0.5 12810.0
30. NNH+H=N2+H2 1.00E+14 0.0 0.0
31. NNH+N=NH+N2 3.00E+13 0.0 8370.0
32. NNH+NH=N2+NH2 2.00E+11 0.5 8370.0
33. NNH+NH2=N2+NH3 1.00E+13 0.0 0.0
34. NNH+NNH=N2H2+N2 1.00E+13 0.0 16750.0
35. N2H2+M=NNH+H+M 5.00E+16 0.0 209340.0
N2 Enhanced by 2.000E+00
H2 Enhanced by 2.000E+00
36. N2H2+M=NH+NH+M 3.16E+16 0.0 416170.0
N2 Enhanced by 2.000E+00
H2 Enhanced by 2.000E+00
37. N2H2+H=NNH+H2 8.50E+04 2.6 -963.0
38. N2H2+N=NNH+NH 1.00E+06 2.0 0.0
39. N2H2+NH=NNH+NH2 1.00E+13 0.0 25120.0
40. N2H2+NH2=NH3+NNH 8.80E-02 4.0 -6740.0
41. N2H3+M=NH2+NH+M 5.00E+16 0.0 251210.0
42. N2H3+M=N2H2+H+M 1.00E+17 0.0 138160.0
43. N2H3+H=N2H2+H2 1.00E+13 0.0 0.0
44. N2H3+H=NH2+NH2 5.00E+13 0.0 8370.0
45. N2H3+H=NH+NH3 1.00E+11 0.0 0.0
46. N2H3+N=N2H2+NH 1.00E+06 2.0 0.0
47. N2H3+NH=N2H2+NH2 2.00E+13 0.0 0.0
48. N2H3+NH2=N2H2+NH3 1.00E+11 0.5 0.0
49. N2H3+NNH=N2H2+N2H2 1.00E+13 0.0 16750.0
50. N2H3+N2H3=NH3+NH3+N2 3.00E+12 0.0 0.0
51. N2H3+N2H3=N2H4+N2H2 1.20E+13 0.0 0.0
52. N2H4(+M)=NH2+NH2(+M) 5.00E+14 0.0 251210.0
Low pressure limit: 0.15000E+16 0.00000E+00 0.16328E+06
N2 Enhanced by 2.400E+00
NH3 Enhanced by 3.000E+00
N2H4 Enhanced by 4.000E+00
53. N2H4+M=N2H3+H+M 1.00E+15 0.0 266280.0
N2 Enhanced by 2.400E+00
NH3 Enhanced by 3.000E+00
N2H4 Enhanced by 4.000E+00
54. N2H4+H=N2H3+H2 7.00E+12 0.0 10470.0
55. N2H4+H=NH2+NH3 2.40E+09 0.0 12980.0
56. N2H4+N=N2H3+NH 1.00E+10 1.0 8370.0
57. N2H4+NH=NH2+N2H3 1.00E+09 1.5 8370.0
58. N2H4+NH2=N2H3+NH3 1.80E+06 1.7 -5780.0
59. N3+N3=N2+N2+N2 8.43E+11 0.0 0.0
60. H+N3=N2+NH 6.03E+13 0.0 0.0
61. N3+N=N2+N2 8.43E+13 0.0 0.0
Table 2S. Results of the quantum chemical study. Units are Å, amu, hartree, and cm1.
hn3Structures / Electronic energy (hartree): / Vibrational frequencies (cm^-1)
BH&HLYP/aug-cc-pvdz[Opt] / BH&HLYP/aug-cc-pvdz[Opt]
N / X / Y / Z / BH&HLYP/aug-cc-pvdz[Opt] / -164.7059545 / 555 / 3606 / -
7 / -1.706458 / -2.322950 / -0.066073 / CCSD(T)/aug-cc-pvdz / -164.4115719 / 634 / - / -
1 / -2.603872 / -2.190261 / 0.386900 / CCSD(T)/aug-cc-pvtz / -164.5505160 / 1246 / - / -
7 / -0.810269 / -1.879217 / 0.660744 / 1356 / - / -
7 / 0.094694 / -1.522562 / 1.211232 / CCSD/aug-cc-pvdz[Opt] / -164.3881483 / 2391 / - / -
- / - / - / - / CCSD(T)/aug-cc-pvdz / -164.4150842
N / X / Y / Z / CCSD/aug-cc-pvdz[Opt]
7 / -0.023544 / 0.000073 / -0.001217 / 504 / 3499 / -
1 / -0.002753 / 0.000023 / 1.024502 / 575 / - / -
7 / 1.171020 / -0.000173 / -0.406034 / 1180 / - / -
7 / 2.182935 / -0.001512 / -0.932441 / 1315 / - / -
2234 / - / -
h_hn3_2
Structures / Electronic energy (hartree): / Vibrational frequencies (cm^-1)
BH&HLYP/aug-cc-pvdz[Opt] / BH&HLYP/aug-cc-pvdz[Opt]
N / X / Y / Z / BH&HLYP/aug-cc-pvdz[Opt] / -165.1982569 / -954 / 1216 / -
7 / 1.102971 / -0.340121 / -0.089828 / CCSD(T)/aug-cc-pvdz / - / 347 / 1349 / -
1 / 1.634233 / 0.358120 / -0.595311 / CCSD(T)/aug-cc-pvtz / - / 485 / 2314 / -
7 / -0.053258 / -0.416761 / -0.551534 / 575 / 3625 / -
7 / -1.080145 / -0.732823 / -0.877814 / CCSD/aug-cc-pvdz[Opt] / - / 665 / - / -
1 / 2.049278 / -1.734053 / -0.323691 / CCSD(T)/aug-cc-pvdz / -
- / - / - / - / -
- / - / - / - / Barrier width / 1.5565676 / - / - / -
n_hn3_1
Structures / Electronic energy (hartree): / Vibrational frequencies (cm^-1)
BH&HLYP/aug-cc-pvdz[Opt] / BH&HLYP/aug-cc-pvdz[Opt]
N / X / Y / Z / BH&HLYP/aug-cc-pvdz[Opt] / -219.2540176 / 124 / 1099 / -
7 / 2.010879 / -0.248341 / -0.521358 / CCSD(T)/aug-cc-pvdz / -218.8587230 / 494 / 1356 / -
7 / 0.955204 / 0.065514 / -1.028341 / CCSD(T)/aug-cc-pvtz / -219.0291815 / 622 / 2108 / -
7 / -0.011866 / 0.421508 / -1.502013 / 661 / -2281 / -
1 / 2.007258 / -1.540181 / -0.348293 / CCSD/aug-cc-pvdz[Opt] / - / 735 / - / -
7 / 1.909707 / -2.733608 / -0.229858 / CCSD(T)/aug-cc-pvdz / -
- / - / - / - / -
- / - / - / - / Barrier width / 0.9160000 / - / - / -
n_hn3_2
Structures / Electronic energy (hartree): / Vibrational frequencies (cm^-1)
BH&HLYP/aug-cc-pvdz[Opt] / BH&HLYP/aug-cc-pvdz[Opt]
N / X / Y / Z / BH&HLYP/aug-cc-pvdz[Opt] / -219.2496336 / -713 / 1044 / -
7 / -1.505783 / -2.497576 / -0.071051 / CCSD(T)/aug-cc-pvdz / -218.8568686 / 160 / 1294 / -
1 / -2.442477 / -2.667215 / 0.275842 / CCSD(T)/aug-cc-pvtz / -219.0247802 / 460 / 2022 / -
7 / -0.916439 / -1.638695 / 0.683738 / 495 / 3504 / -
7 / 0.032458 / -1.292811 / 1.220495 / CCSD/aug-cc-pvdz[Opt] / - / 565 / - / -
7 / -0.793466 / -4.207487 / -0.099963 / CCSD(T)/aug-cc-pvdz / -
n_hn3_3
Structures / Electronic energy (hartree): / Vibrational frequencies (cm^-1)
BH&HLYP/aug-cc-pvdz[Opt] / BH&HLYP/aug-cc-pvdz[Opt]
N / X / Y / Z / BH&HLYP/aug-cc-pvdz[Opt] / -219.2217627 / 379 / 1384 / -
7 / -1.878382 / -1.829296 / 0.295537 / CCSD(T)/aug-cc-pvdz / -218.8279226 / 452 / 1645 / -
1 / -2.362847 / -2.679099 / 0.027056 / CCSD(T)/aug-cc-pvtz / -218.9954454 / 530 / 3584 / -
7 / -0.693578 / -2.135091 / 0.626188 / 652 / -920 / -
7 / 0.309036 / -1.618969 / 1.012083 / CCSD/aug-cc-pvdz[Opt] / - / 1162 / - / -
7 / -0.479411 / -3.794201 / 0.466229 / CCSD(T)/aug-cc-pvdz / -
n_hn3_4
Structures / Electronic energy (hartree): / Vibrational frequencies (cm^-1)
BH&HLYP/aug-cc-pvdz[Opt] / BH&HLYP/aug-cc-pvdz[Opt]
N / X / Y / Z / BH&HLYP/aug-cc-pvdz[Opt] / -219.2511860 / -772 / 1279 / -
7 / -0.702392 / -0.266554 / 0.784730 / CCSD(T)/aug-cc-pvdz / -218.8566856 / 197 / 1298 / -
1 / -1.594370 / 0.196080 / 0.925780 / CCSD(T)/aug-cc-pvtz / -219.0262522 / 243 / 1940 / -
7 / -0.601042 / -1.260260 / 1.507759 / 612 / 3583 / -
7 / -0.028628 / -2.193256 / 1.916252 / CCSD/aug-cc-pvdz[Opt] / - / 639 / - / -
7 / 1.535557 / -2.346723 / 1.149526 / CCSD(T)/aug-cc-pvdz / -
n3
Structures / Electronic energy (hartree): / Vibrational frequencies (cm^-1)
BH&HLYP/aug-cc-pvdz[Opt] / BH&HLYP/aug-cc-pvdz[Opt]
N / X / Y / Z / BH&HLYP/aug-cc-pvdz[Opt] / -164.0651137 / 510 / - / -
7 / -1.684422 / -2.214041 / -0.080242 / CCSD(T)/aug-cc-pvdz / -163.7673419 / 633 / - / -
7 / -0.788677 / -1.879702 / 0.591313 / CCSD(T)/aug-cc-pvtz / -163.8995360 / 1456 / - / -
7 / 0.107458 / -1.543966 / 1.262012 / 1728 / - / -
n2
Structures / Electronic energy (hartree): / Vibrational frequencies (cm^-1)
BH&HLYP/aug-cc-pvdz[Opt] / BH&HLYP/aug-cc-pvdz[Opt]
N / X / Y / Z / BH&HLYP/aug-cc-pvdz[Opt] / -109.4827318 / 2586 / - / -
7 / 0.000000 / 0.000000 / 0.545239 / CCSD(T)/aug-cc-pvdz / -109.2927886 / - / - / -
7 / 0.000000 / 0.000000 / -0.545239 / CCSD(T)/aug-cc-pvtz / -109.3803583 / - / - / -
nh
Structures / Electronic energy (hartree): / Vibrational frequencies (cm^-1)
BH&HLYP/aug-cc-pvdz[Opt] / BH&HLYP/aug-cc-pvdz[Opt]
N / X / Y / Z / BH&HLYP/aug-cc-pvdz[Opt] / -55.2097946 / 3387 / - / -
7 / -0.228139 / 0.329319 / 0.000000 / CCSD(T)/aug-cc-pvdz / -55.1055657 / - / - / -
1 / -0.617555 / 1.288335 / 0.000000 / CCSD(T)/aug-cc-pvtz / -55.1451107 / - / - / -
nh2
Structures / Electronic energy (hartree): / Vibrational frequencies (cm^-1)
BH&HLYP/aug-cc-pvdz[Opt] / BH&HLYP/aug-cc-pvdz[Opt]
N / X / Y / Z / BH&HLYP/aug-cc-pvdz[Opt] / -55.8589788 / 1562 / - / -
7 / -0.233123 / 0.333362 / 0.000000 / CCSD(T)/aug-cc-pvdz / -55.7515947 / 3484 / - / -
1 / -0.612708 / 1.282105 / 0.000000 / CCSD(T)/aug-cc-pvtz / - / 3579 / - / -
1 / 0.778305 / 0.479003 / 0.000000 / - / - / -
hn2
Structures / Electronic energy (hartree): / Vibrational frequencies (cm^-1)
BH&HLYP/aug-cc-pvdz[Opt] / BH&HLYP/aug-cc-pvdz[Opt]
N / X / Y / Z / BH&HLYP/aug-cc-pvdz[Opt] / -109.9870695 / 1145 / - / -
7 / -1.663195 / -2.374856 / 0.022341 / CCSD(T)/aug-cc-pvdz / -109.7855721 / 1975 / - / -
1 / -2.613410 / -2.236869 / 0.432509 / CCSD(T)/aug-cc-pvtz / -109.8742071 / 3047 / - / -
7 / -0.856767 / -1.580019 / 0.311898 / - / - / -
nh2_hn3_01
Structures / Electronic energy (hartree): / Vibrational frequencies (cm^-1)
BH&HLYP/aug-cc-pvdz[Opt] / BH&HLYP/aug-cc-pvdz[Opt]
N / X / Y / Z / BH&HLYP/aug-cc-pvdz[Opt] / -220.5560701 / -2191 / 630 / 1433
7 / 1.607868 / -0.412746 / -0.064990 / CCSD(T)/aug-cc-pvdz / -220.1570836 / 80 / 719 / 1591
7 / 1.172506 / -0.130162 / -1.164312 / CCSD(T)/aug-cc-pvtz / - / 134 / 741 / 2235
7 / 0.752344 / 0.206485 / -2.157440 / 423 / 1173 / 3540
1 / 2.072061 / -1.523122 / -0.025595 / CCSD/aug-cc-pvdz[Opt] / - / 530 / 1369 / 3639
7 / 2.151989 / -2.797767 / -0.079546 / CCSD(T)/aug-cc-pvdz / -
1 / 1.981652 / -3.098026 / -1.036203 / -
1 / 1.377313 / -3.162446 / 0.469102 / Barrier width / 0.7027000 / - / - / -
nh2_hn3_02
Structures / Electronic energy (hartree): / Vibrational frequencies (cm^-1)
BH&HLYP/aug-cc-pvdz[Opt] / BH&HLYP/aug-cc-pvdz[Opt]
N / X / Y / Z / BH&HLYP/aug-cc-pvdz[Opt] / -220.5395300 / -790 / 644 / 1564
7 / -2.390141 / -4.483745 / 0.515325 / CCSD(T)/aug-cc-pvdz / -220.1431575 / 121 / 838 / 2133
1 / -2.409975 / -5.492715 / 0.561830 / CCSD(T)/aug-cc-pvtz / - / 190 / 937 / 3533
7 / -2.631509 / -3.994644 / 1.668493 / 483 / 1089 / 3632
7 / -2.455769 / -3.248017 / 2.513343 / CCSD/aug-cc-pvdz[Opt] / - / 511 / 1363 / 3658
7 / -0.638388 / -4.291570 / -0.221254 / CCSD(T)/aug-cc-pvdz / -
1 / -0.225558 / -3.761106 / 0.542984 / -
1 / -0.905682 / -3.584836 / -0.900607 / - / - / -
nh2_hn3_04
Structures / Electronic energy (hartree): / Vibrational frequencies (cm^-1)
BH&HLYP/aug-cc-pvdz[Opt] / BH&HLYP/aug-cc-pvdz[Opt]
N / X / Y / Z / BH&HLYP/aug-cc-pvdz[Opt] / -220.5399100 / -661 / 625 / 1564
7 / -1.469754 / -2.442214 / 1.954357 / CCSD(T)/aug-cc-pvdz / -220.1417915 / 126 / 883 / 1982
1 / -2.141690 / -2.289311 / 2.699345 / CCSD(T)/aug-cc-pvtz / - / 198 / 925 / 3526
7 / -0.384739 / -2.808879 / 2.437027 / 438 / 1275 / 3582
7 / 0.752612 / -3.007981 / 2.358065 / CCSD/aug-cc-pvdz[Opt] / - / 576 / 1326 / 3632
7 / 1.466966 / -2.206627 / 0.882422 / CCSD(T)/aug-cc-pvdz / -
1 / 2.440077 / -2.404734 / 1.098599 / -
1 / 1.339307 / -1.228997 / 1.138486 / - / - / -
nh3
Structures / Electronic energy (hartree): / Vibrational frequencies (cm^-1)
BH&HLYP/aug-cc-pvdz[Opt] / BH&HLYP/aug-cc-pvdz[Opt]
N / X / Y / Z / BH&HLYP/aug-cc-pvdz[Opt] / -56.5305369 / 1044 / 3720 / -
7 / -0.326768 / 0.333321 / -0.033723 / CCSD(T)/aug-cc-pvdz / -56.4249954 / 1693 / - / -
1 / -0.642533 / 1.146389 / -0.540309 / CCSD(T)/aug-cc-pvtz / -56.4804577 / 1694 / - / -
1 / 0.681352 / 0.332325 / -0.065660 / 3588 / - / -
1 / -0.644543 / -0.478587 / -0.540900 / CCSD/aug-cc-pvdz[Opt] / - / 3720 / - / -
hn3_ar_vdw01
Structures / Electronic energy (hartree): / Vibrational frequencies (cm^-1)
BH&HLYP/aug-cc-pvdz[Opt] / BH&HLYP/aug-cc-pvdz[Opt]
N / X / Y / Z / BH&HLYP/aug-cc-pvdz[Opt] / -692.2438213 / 26 / 1247 / -
7 / -0.691015 / 0.179463 / -0.494832 / CCSD(T)/aug-cc-pvdz / -691.3824559 / 40 / 1359 / -
1 / -0.273725 / 1.083969 / -0.304913 / CCSD(T)/aug-cc-pvtz / - / 58 / 2390 / -
7 / -1.922392 / 0.284774 / -0.488047 / 557 / 3607 / -
7 / -3.038841 / 0.236043 / -0.511388 / CCSD/aug-cc-pvdz[Opt] / -691.3563365 / 634 / - / -
18 / 1.709333 / 3.132014 / 0.103180 / CCSD(T)/aug-cc-pvdz / -691.3860023
- / - / - / - / CCSD/aug-cc-pvdz[Opt]
N / X / Y / Z / 10 / 1180 / -
7 / 1.174069 / 0.878088 / -0.000719 / 51 / 1317 / -
1 / 0.281006 / 0.374015 / 0.007429 / 108 / 2236 / -
7 / 2.096761 / 0.018498 / 0.000295 / 505 / 3510 / -
7 / 3.039813 / -0.622743 / -0.000299 / 576 / - / -
18 / -2.469750 / -0.127273 / -0.000132
hn3_ar_vdw02
Structures / Electronic energy (hartree): / Vibrational frequencies (cm^-1)
BH&HLYP/aug-cc-pvdz[Opt] / BH&HLYP/aug-cc-pvdz[Opt]
N / X / Y / Z / BH&HLYP/aug-cc-pvdz[Opt] / -692.2438163 / 18 / 1248 / -
7 / -0.628971 / 0.165343 / -0.494702 / CCSD(T)/aug-cc-pvdz / -691.3826030 / 35 / 1358 / -
1 / -0.314412 / 1.111210 / -0.308218 / CCSD(T)/aug-cc-pvtz / - / 102 / 2390 / -
7 / -1.864528 / 0.143001 / -0.513562 / 555 / 3604 / -
7 / -2.969501 / -0.019615 / -0.557945 / CCSD/aug-cc-pvdz[Opt] / -691.3565038 / 634 / - / -
18 / -1.553831 / 3.828000 / 0.202038 / CCSD(T)/aug-cc-pvdz / -691.3862001
- / - / - / - / CCSD/aug-cc-pvdz[Opt]
N / X / Y / Z / 28 / 1181 / -
7 / 0.044913 / 0.000000 / 0.161893 / 58 / 1316 / -
1 / 0.179743 / 0.000000 / 1.178845 / 74 / 2234 / -
7 / 1.188344 / 0.000000 / -0.369644 / 503 / 3502 / -
7 / 2.138326 / 0.000000 / -1.000883 / 574 / - / -
18 / 2.598803 / 0.000000 / 2.921386
n
Electronic energy (hartree):
BH&HLYP/aug-cc-pvdz[Opt] / -54.5812562
CCSD(T)/aug-cc-pvdz / -54.4869816
CCSD(T)/aug-cc-pvtz / -54.5169239
h
Electronic energy (hartree):
BH&HLYP/aug-cc-pvdz[Opt] / -0.4980784
ar
Electronic energy (hartree):
BH&HLYP/aug-cc-pvdz[Opt] / -527.5375827
CCSD(T)/aug-cc-pvdz / -526.9696846
CCSD(T)/aug-cc-pvtz / -
CCSD/aug-cc-pvdz[Opt] / -526.9671591
CCSD(T)/aug-cc-pvdz / -526.9696846
Table 3S. Reaction energy barriers and Ho0 (kJ mol1, ZPE included).
HN3+H=N2+NH2
Energy barrier / Ho0BH&HLYP/aug-cc-pvdz[Opt] / 19.87 / -352.95
Final model (fitted to experiment) / 23.57 / -323.33
HN3+N=N2+NNH (Attack on the 2-nd atom (N))
Energy barrier / Ho0BH&HLYP/aug-cc-pvdz[Opt] / 99.58 / -485.57
CCSD(T)/aug-cc-pvdz / 110.36 / -478.26
CCSD(T)/aug-cc-pvtz / 112.92 / -497.48
Final model (fitted to experiment) / 18.60
HN3+N=Products (Attack on the 3-rd atom (N))
Energy barrier / Ho0BH&HLYP/aug-cc-pvdz[Opt] / 171.84
CCSD(T)/aug-cc-pvdz / 185.45
CCSD(T)/aug-cc-pvtz / 189.03
HN3+N=N2+NNH (Attack on the 4-th atom (N))
Energy barrier / Ho0BH&HLYP/aug-cc-pvdz[Opt] / 94.61 / -485.57
CCSD(T)/aug-cc-pvdz / 109.95 / -478.26
CCSD(T)/aug-cc-pvtz / 108.16 / -497.48
HN3+N=NH+N3 (Attack on the 1-st atom (H))
Energy barrier / Ho0BH&HLYP/aug-cc-pvdz[Opt] / 71.67 / 16.11
CCSD(T)/aug-cc-pvdz / 89.10 / 51.15
CCSD(T)/aug-cc-pvtz / 84.97 / 43.66
HN3+NH2=NH3+N3
Energy barrier / Ho0BH&HLYP/aug-cc-pvdz[Opt] / 22.22 / -76.22
CCSD(T)/aug-cc-pvdz / 14.92 / -72.16
Final model / 14.92 / -72.16
HN3+NH2=Products (Attack on the 2-nd atom (N))
Energy barrier / Ho0BH&HLYP/aug-cc-pvdz[Opt] / 80.34
CCSD(T)/aug-cc-pvdz / 66.18
HN3+NH2=Products (Attack on the 4-th atom (N))
Energy barrier / Ho0BH&HLYP/aug-cc-pvdz[Opt] / 79.13
CCSD(T)/aug-cc-pvdz / 69.55
Comments on individual reactions
N + HN3 → Products
Two channels are possible:
N + HN3 → NH + N3
N + HN3 → N2H + N2 → H + N2 + N2
The first channel results from an abstraction of H atom by N. The second channel can result from N atom attack on the N of HN3 nearest to H (HN(…N)NN) or the farthest from H (HNNN(…N)). There is only one experimental study of this reaction, performed by Le Bras and Combourieu [1]. The rate constant obtained at 298 K was 2.7×109 cm3 mol1 s1. The energy barriers obtained in quantum chemical calculations are large. The room temperature overall rate constant calculated using transition state theory and the above results is much lower than the experimental value of Le Bras and Combourieu, with many orders of magnitude difference. In modeling, the energy of the transition state of the second channel were fitted to reproduce the rate constant of Le Bras and Combourieu. The first channel was not used because of the endothermicity exceeding the barrier required for fitting the experimental rate constant.
NH2 + HN3 → Products
No experimental data are available for this reaction. An earlier computational study was performed by Henon and Bohr [2]. In the current work, quantum chemical calculations were performed for the reaction of N atoms with HN3. The methods were BH&HLYP/aug-cc-pvdz for geometry optimization and vibrational frequencies and CCSD(T)/aug-cc-pvtz for single-point energy calculations. Radical attack on the H atom (atom 1) and nitrogen atoms 2 and 4 were studied. Energy barrier for attack on H (producing NH3 + N3) is only 14.9 kJ mol1, whereas those for the other two reaction channels are 66.2 and 69.6 kJ mol1, making these two channels unimportant. Rate constants obtained in transition state theory calculations are larger than those derived by Henon and Bohr by approximately two orders of magnitude, due to the lower energy barrier but also due to the fact that calculations performed in that earlier study did not include the partition function of the hindered internal rotation about the forming H2N-H bond, as described in their article, which resulted in too low rate constant values.
References
[1] G. Le Bras, J. Combourieu, Int. J. Chem. Kinet. 5 (1973) 559-576.
[2] E. Henon, F. Bohr, J. Molec. Struc. - Theochem. 531 (2000) 283-299.
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