H + CH2 (+M) -> CH3 (+M)

k_inf = 2.50E+16/T^0.8 cm3/mol s

F_cent = (1-0.68) exp(-T/78) + 0.68 exp(-T/1995) + exp(-5590/T)

Third-body efficiencies:

N2                    1.0 
H2     Enhanced by    2.0 
H2O    Enhanced by    6.0 
CH4    Enhanced by    2.0 
CO     Enhanced by    1.5 
CO2    Enhanced by    2.0 
C2H6   Enhanced by    3.0 
AR     Enhanced by    0.7 

SOURCE:

RRKM calculations.

The expression for k_inf is an estimate derived from the value of Stewart et al. (1989) for reaction
52 H + CH3(+M) -> CH4(+M).

k_o and F_cent for N2 are calculated by the method of Troe (1977), using the parameters
delta-E(0 K) = 0.00 kcal/mol
delta-H(0 K) = -108.7 kcal/mol
< delta-E> (average energy transferred per collision) = 0.30 kcal/mol
The Lennard-Jones parameters: sigma (CH3-N2) = 3.78 A, epsilon = 103 K
I+/I (used to compute the Waage-Rabinovitch correction for rotational energy) = 6.8
v = 3184, 3184, 3000, 1383, 1383, 580 cm^(-1)

COMMENTS:

At 2500 K, k_o for CH3 decompostion in Ar of 2.2E8 (cm3/mol s) compares favorably to the shock tube measurement of 1.9E8 (cm3/mol s) by Markus et al. (1992).

The pressure broadening is expressed in the Troe form.

Served as an optimization variable in the GRI-Mech 1.2 and 2.1 releases. The rate coefficient was not changed.

REFERENCES:

Markus et al. (1992)

Markus, M.W., Woiki, D., and Roth P. (1992) 24th Symposium (International) on Combustion, p. 581.

Stewart et al. (1989)

Stewart, P.H., Smith, G.P., and Golden, D.M. (1989) Int. J. Chem. Kinet. 21, 923.

Troe (1977)

Troe, J. (1977) J.Chem.Phys. 66, 4745.

                        PRESSURE = 0.1 atm N2  
______________________________________________________________________
    Temp      delta-S     delta-H      kf          kr         Keq     
     (K)    (cal/mol K)  (kcal/mol) ----(mol,cm3,s)-----   (cm3/mol)  
______________________________________________________________________
                                                                      
     300       -27.5      -110.8    1.92E+13    1.64E-66    1.17E+79
     500       -29.5      -111.5    5.59E+12    6.77E-35    8.25E+46
    1000       -31.2      -112.7    5.96E+11    1.11E-11    5.39E+22
    1500       -31.6      -113.2    1.34E+11    2.80E-04    4.79E+14
    2000       -31.6      -113.3    4.52E+10    9.46E-01    4.78E+10
    2500       -31.6      -113.2    1.95E+10    9.73E+01    2.00E+08
    3000       -31.5      -113.0    9.82E+09    1.82E+03    5.40E+06
______________________________________________________________________


                        PRESSURE = 1 atm N2    
______________________________________________________________________
    Temp      delta-S     delta-H      kf          kr         Keq     
     (K)    (cal/mol K)  (kcal/mol) ----(mol,cm3,s)-----   (cm3/mol)  
______________________________________________________________________
                                                                      
     300       -27.5      -110.8    8.10E+13    6.92E-66    1.17E+79
     500       -29.5      -111.5    3.15E+13    3.82E-34    8.25E+46
    1000       -31.2      -112.7    4.51E+12    8.36E-11    5.39E+22
    1500       -31.6      -113.2    1.09E+12    2.27E-03    4.79E+14
    2000       -31.6      -113.3    3.79E+11    7.94E+00    4.78E+10
    2500       -31.6      -113.2    1.68E+11    8.41E+02    2.00E+08
    3000       -31.5      -113.0    8.71E+10    1.61E+04    5.40E+06
______________________________________________________________________


                        PRESSURE = 10 atm N2   
______________________________________________________________________
    Temp      delta-S     delta-H      kf          kr         Keq     
     (K)    (cal/mol K)  (kcal/mol) ----(mol,cm3,s)-----   (cm3/mol)  
______________________________________________________________________
                                                                      
     300       -27.5      -110.8    1.75E+14    1.49E-65    1.17E+79
     500       -29.5      -111.5    8.18E+13    9.92E-34    8.25E+46
    1000       -31.2      -112.7    1.90E+13    3.52E-10    5.39E+22
    1500       -31.6      -113.2    6.13E+12    1.28E-02    4.79E+14
    2000       -31.6      -113.3    2.48E+12    5.19E+01    4.78E+10
    2500       -31.6      -113.2    1.21E+12    6.04E+03    2.00E+08
    3000       -31.5      -113.0    6.71E+11    1.24E+05    5.40E+06
______________________________________________________________________