Caltech isoprene scheme

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NOTE: This page is for documentation of new isoprene chemistry to be included in v9-02.

'Previous page of description can be found here New isoprene scheme prelim.

Implementation of the Paulot isoprene scheme

A full reference of all reactions used can be found in this document.

Species

New species added

Species Formula Note
MAOPO2 CH2OH-CHOO*CH3C(O)OOH Peroxy radical from MAOP (addition on the double bond)
ISOPNB C5H9NO4 Isoprene nitrate Beta
ISOPND C5H9NO4 Isoprene nitrate Delta
HC5 C55H8O2 Hydroxycarbonyl with 5C
DIBOO Dibble peroxy radical
MF3 Methyl furan but I didn’t use it
HC5OO Peroxy radical from HC5 (old IAO2?)
DHMOB C5H8O4 See Paulot et al., ACP (2009)
MOBA 5C acid from isoprene
MOBAOO RO2 from MOBA
ISOPNBO2 RO2 from ISOPND
ISOPNDO2 RO2 from ISOPND
PROPNN Propanone nitrate
ETHLN Ethanal nitrate
DHB Dihydroxybutanone (but removed)
MACRN Nitrate from MVK
MVKN Nitrate from MACR
PYAC Pyruvic acid
IEPOX Isoprene epoxide
IEPOXOO RO2 from IEPOX
PYPAN Pyruvic acid PAN
PYPO2 RO2 associated with PYPAN
ATOOH ATO2 peroxide
DRYPMNN Dry deposition for the different species
DRYALPH
DRYLIMO
DRYISOPND
DRYISOPNB
DRYRIP
DRYIEPOX
DRYMACRN
DRYMVKN
DRYPROPNN
DRYHCOOH
DRYACTA
DRYPYPAN

Species emitted and deposited

Species emitted Species deposited
NO NO2
NO2 O3
CO PAN
ALK4 HNO3
ISOP CH2O
ACET N2O5
PRPE H2O2
C3H8 PMN
C2H6 PPN
MEK R4N2
ALD2
CH2O PMNN
HNO3 IEPOX
O3 RIP
ISOPND
ISOPNB
PROPNN
MACRN
MVKN
HCOOH
ACTA

Henry's law constant

Species Heff(moles L-1 atm-1 ) ΔH/R (K) Reference
HCOOH 167,000 (pH = 5) -6100 Ito et al., 2007
CH3COOH 11,400 (pH = 5) -6300 Ito et al., 2007
MOBA 23000 -6300 Ito et al., 2007
GLYC 41000 -4600 Ito et al., 2007
GLYX 360000 -7200 Schweitzer et al., 1998
MGLY 3700 -7500 Ito et al., 2007
δ-ISOPN (ISOPND) 17000 -9200 Ito et al., 2007
β-ISOPN (ISOPND) 17000 -9200 Ito et al., 2007
MACRN 17000 -9200 Ito et al., 2007
MVKN 17000 -9200 Ito et al., 2007
PROPNN 1000 0 R. Sander (NITROOXYACETONE)
RIP 1.7e6 0 Marais et al., 2012
IEPOX 1.3e8 0 Marais et al., 2012
MAP 840 (f0 =1, reactive) -5300 R. Sander
HNO3 210000 -8700

Species removed from standard chemistry

Species Formula Note
GCO3 HOCH2C(O)OO hydroxy peroxyacetyl radical
GLCO3 HCOHC(O)OO peroxyacyl from GLYX
GLP HCOHC(O)OOH peroxide from GLCO3
GLPAN HCOHC(O)OONO2 peroxyacylnitrate from GLCO3
GP HOCH2C(O)OOH peroxide from GCO3
GPAN HOCH2C(O)OONO2 peroxyacylnitrate from GCO3
ISN1 HOCH2C(OO)(CH3)CH(ONO2)CH2OH RO2 from ISN2
RIO1 HOCH2C(OO)(CH3)CH=CHOH RO2 from isoprene oxidation products
IAO2 HOCH2C(CH3)(OO)CH(OH)CHO RO2 from isoprene oxidation products
MVN2 O2NOCH2CH(OO)C(O)CH3 RO2 from MVK+NO3

Species Activated from standard chemistry

Species Formula Note
GLYX CHOCHO glyoxal
HCOOH HCOOH formic acid
IALD HOCH2C(CH3)=CHCHO hydroxy carbonyl alkenes from isoprene

Reactions

New reactions

No Reaction Rate Constant Reference Note
1 ATOOH +OH = ATO2 +H2O 2.66E-12exp(200/T) Rate uses MP+OH
2 ATOOH +OH = MGLY +OH +H2O 1.14E-12exp(200/T) Rate uses MP+OH
3 RIO2 + NO = 0.883NO2 + 0.783HO2 + 0.660CH2O + 0.400MVK + 0.260MACR + 0.070ISOPND + 0.047ISOPNB + 0.123HC5 + 0.1DIBOO 2.7E-12 exp(350/T) Paulot 2009a HNO3 channel deleted since nitrate is treated explicitly;paulothn2009;neglect methylfuran formation (increase the yield of other products)
4 VRO2 + NO = 0.88NO2 + 0.35HO2 + 0.35CH2O + 0.53MCO3 + 0.53GLYC + 0.35MGLY + 0.12MVKN 2.7E-12 exp(350/T) Paulot 2009a
5 MRO2 + NO = 0.85NO2 + 0.85HO2 + 0.122MGLY + 0.728HAC + 0.728CO + 0.122CH2O + 0.15MACRN 2.7E-12 exp(350/T) Paulot 2009a This is modified based on Chuong et al. (2004).It was equally yield for MGLY and HAC in Paulot 2009 ACP, according to Peeters decomposition scheme.
6 MAN2 + NO = 1.5NO2 + 0.5CH2O + 0.5MGLY + 0.5PROPNN + 0.5CO + 0.5OH 2.7E-12 exp(350/T) Tyndall ETO2+NO
7 ATO2 + HO2 = 0.15MCO3 + 0.15OH + 0.15CH2O + 0.85ATOOH 8.60E-13 exp(700/T) Dillon et al. (2008) Tyndall, Dillon et al. (ACP 2008) cycling 15%,reduce the recyling by 5% compared to previous version to be fully consistent with Dillon et al.
8 KO2 + HO2 = 0.15OH +0.15ALD2 +0.15 MCO3 + 0.85 ATOOH 2.91E-13*EXP(1300/T)[1-EXP(-0.245*n)], n=4 MCM assuming 15% recycling of OH
9 RIO2 + HO2= 0.88RIP + 0.12OH + 0.047MACR + 0.073MVK + 0.12HO2 + 0.12CH2O 2.91E-13*EXP(1300/T)[1-EXP(-0.245*n)], n=5 Paulot 2009b Rate is from Saunders et al. (2003)
10 VRO2 + HO2 = 0.1VRP + 0.68OH + 0.578GLYC + 0.578MCO3 + 0.187MEK + 0.102HO2 + 0.102CH2O + 0.102MGLY + 0.033RCHO 2.91E-13*EXP(1300/T)[1-EXP(-0.245*n)], n=4 ??? crounse2010
11 MRO2 + HO2 = 1.0MRP 2.91E-13*EXP(1300/T)[1-EXP(-0.245*n)], n=4 isomerization of MRO2 is included in another reaction.
12 MAN2 + HO2 = 0.075PROPNN + 0.075CO + 0.075HO2 + 0.075MGLY + 0.075CH2O + 0.075NO2 + 0.15OH + 0.85ISNP 2.91E-13*EXP(1300/T)[1-EXP(-0.245*n)],n=4 assume 15% recycling of OH, the rest goes to ISNP
13 INO2 + HO2 = INPN 2.91E-13*EXP(1300/T)[1-EXP(-0.245*n)], n=5 Xie et al. (2012) See nighttime chemistry
14 RIO2 + MO2 = 1.1HO2 + 1.22CH2O + 0.280MVK + 0.180MACR + 0.3HC5 + 0.24MOH + 0.24ROH 8.37E-14
15 RIO2 + RIO2 = 1.28HO2 + 0.92CH2O + 0.56MVK + 0.36MACR + 0.48ROH + 0.5HC5 1.54E-13
16 HC5OO + MO2 = 0.50HO2 + 0.33CO + 0.09H2 + 0.18HAC + 0.13GLYC + 0.29MGLY + 0.25MEK + 0.95CH2O + 0.25MOH + 0.25ROH + 0.5HO2 8.37E-14 Tyndall MO2+MO2 Atkinson97 RO2+RO2; HC5OO=old IAO2
17 MRO2 + MO2 = 0.595HAC + 0.255MGLY + 0.595CO + 1.255CH2O + 1.7HO2 + 0.150ROH 8.37E-14
18 MAN2 + MO2 = 0.375PROPNN + 0.375CO + 0.375HO2 + 0.375MGLY + 0.375CH2O + 0.375NO2 + 0.250CH2O + 0.250R4N2 8.37E-14
19 INO2 + MO2 = 0.55NO2 + 0.40HO2 + 0.425R4N2 + 0.025NO2 + 0.05MACR + 0.08CH2O + 0.03MVK + 0.25RCHO + 0.75CH2O + 0.25MOH + 0.25ROH + 0.5HO2 8.37E-14
20 RCO3 + HO2 = 0.410RP + 0.150RCOOH + 0.150O3 + 0.440OH + 0.440ETO2 4.3E-13exp(1040/T) MCM v3.2 Branching ratio is from MCMv3.2
21 MAO3 + HO2 = 0.44OH +0.15O3 + 0.59CH2O + 0.39MO2 + 0.41MAOP + 0.39CO 4.3E-13exp(1040/T) use MCM, 44% OH channel, 15% O3 channel, 41% peroxide channel.
22 PMN + OH = HAC + CO + NO2 2.90E-11 MCM v3.2 rates and products all from MCM
30 GLYC + OH = 0.850CH2O +0.260CO2 + 0.580CO + 0.260OH + 0.740HO2 + 0.155GLYX FRAC=1-11.0729*exp(-1/73T) Rate=8.00E-12*FRAC Paulot 2009a Butkovskaya 2006 companion paper and Paulot 2009
31 GLYC + OH= HCOOH + 0.190OH +0.190CO + 0.810CO2 + 0.810HO2 FRAC=1-11.0729*exp(-1/73T) Rate=8.00E-12*(1-FRAC) Paulot 2009a Butkovskaya 2006 companion paper and Paulot 2009
32 GLYX+OH = HO2+2CO 3.1E-12exp(340/T) IUPAC2008 JMAO
33 MACR + OH = 0.53MAO3 +0.47MRO2 8.0E-12exp(380/T) Paulot 2009a MAO3(=MCO3 in the paper); MRO2(=MACROO in the paper)
34 HAC + OH = MGLY +HO2 FRAC=1-23.7*exp(1/60T) Rate=2.15E-12exp(305/T)*FRAC Paulot 2009a Butkovskaya JPC A (a,b)2006 and Paulot 2009a
35 HAC + OH = 0.5HCOOH + OH +0.5ACTA +0.5CO2 + 0.5CO + 0.5MO2 FRAC=1-23.7*exp(1/60T) Rate=2.15E-12exp(305/T)*(1-FRAC) Paulot 2009a Butkovskaya JPC A (a,b)2006 and Paulot 2009a
38 PRPN+OH=0.209PRN1+0.791OH+0.791PROPNN 8.78E-12exp(200/T) Branching ratio is determined by alpha and beta Hydrogen position (Kwok et al., 1995).
39 ETP+OH=0.64OH+0.36ETO2+0.60ALD2 5.18E-12exp(200/T) Branching ratio is determined by alpha and beta Hydrogen position (Kwok et al., 1995).
40 RA3P+OH=0.64OH+0.36A3O2+0.64RCHO 5.18E-12exp(200/T) Branching ratio is determined by alpha and beta Hydrogen position (Kwok et al., 1995).
41 RB3P+OH=0.791OH+0.209B3O2+0.791ACET 8.78E-12exp(200/T) Branching ratio is determined by alpha and beta Hydrogen position (Kwok et al., 1995).
42 R4P+OH=0.791OH+0.209R4O2+0.791RCHO 8.78E-12exp(200/T) Branching ratio is determined by alpha and beta Hydrogen position (Kwok et al., 1995).
43 RP+OH=RCO3 6.13E-13exp(200/T) same as MAP+OH
44 PP+OH=0.791OH+0.209PO2+0.791HAC 8.78E-12exp(200/T) Branching ratio is determined by alpha and beta Hydrogen position (Kwok et al., 1995).
45 RIP+OH = 0.387RIO2 + 0.613OH + 0.613HC5 4.75E-12exp(200/T) Paulot 2009b branching ratio is derived below
46 RIP + OH = OH + IEPOX 1.9E-11exp(390/T) Paulot 2009b the yield of IEPOX is > 70% assumed to be 100%
47 IEPOX + OH = IEPOXOO 5.78e-11exp(-400/T) Paulot 2009b
48 IEPOXOO + HO2 = 0.725HAC + 0.275GLYC + 0.275GLYX + 0.275MGLY + 1.125OH + 0.825HO2 + 0.200CO2 + 0.375CH2O + 0.074HCOOH + 0.251CO 2.91E-13*EXP(1300/T)[1-EXP(-0.245*n)], n=5 Paulot 2009b
49 IEPOXOO +NO=0.725HAC+0.275GLYC+0.275GLYX +0.275MGLY +0.125OH +0.825HO2+0.200CO2+0.375CH2O +0.074HCOOH +0.251CO +NO2 2.7E-12exp(350/T) FP: No peroxide was observed
50 IAP+OH =0.654OH+0.654DHMOB+0.346HC5OO 5.31E-12 exp(200/T)
51 VRP+OH=0.791OH+0.791MEK+0.209VRO2 8.78E-12exp(200/T)
52 MRP + OH = MRO2 1.84E-12exp(200/T) This channel is for the abstraction of peroxide H (OOH), which is slow and ignored in MCM v3.2
53 MRP + OH = CO2 + HAC + OH 4.40E-12exp(380/T) This second channel is for the abstraction of aldehydic H, much faster! The rate is from MACR + OH.
54 MAOP + OH = MAO3 6.13E-13exp(200/T) same as MAP+OH
55 MAOP + OH = MAOPO2 3.60E-12exp(380/T)
56 MCO3 + MAOPO2 = 1.0HAC + 2.0CO2 + OH + MO2 1.68E-12exp(500/T)
57 MCO3 + MAOPO2 = 1.0ACTA+1.0MEK 1.87E-13 exp(500/T)
58 MAOPO2 + MO2 = 0.7HAC +0.7CO2+0.7OH+1.0CH2O+0.7HO2+0.3ROH 8.37E-14
59 MAOPO2 + MAOPO2 = 2.0HAC+2.0CO2+2.0OH 8.37E-14
60 MAOPO2 + HO2 = 1.0HAC+1.0CO2+2.0OH 2.91E-13*EXP(1300/T)[1-EXP(-0.245*n)], n=4
61 MAOPO2 + NO = 1.0HAC+1.0CO2+1.0OH+1.0NO2 K* (1-YN) where YN is returned from fyrno3.f K=2.7E-12 exp(350/T) (Xcarbn=4.00E00)
62 MAOPO2 + NO = 1.0HNO3 K* YN where YN is returned from fyrno3.f K=2.7E-12 exp(350/T) (Xcarbn=4.00E00) Not treated explicitly
63 OH + MAP = 1.0MCO3 6.13E-13exp(200/T) From J. Orlando (unpublished results), how confident is this temperature dependence?
64 HC5 + O3 = 0.6MGLY + 0.1OH + 0.12CH2O + 0.28GLYC + 0.3O3 + 0.4CO + 0.2H2 + 0.2HAC + 0.2HCOOH 6.16E-15 exp(-1814/T) HC5=old IALD??
65 R4O2 + MCO3 = MO2 + 0.32ACET + 0.19MEK + 0.27HO2 + 0.32ALD2 + 0.13RCHO + 0.05A3O2 + 0.18B3O2 + 0.32ETO2 1.68E-12 exp(500/T)
66 ATO2+MCO3 = MCO3 +CH2O +MO2 1.68E-12 exp(500/T) IUPAC06
67 RIO2 + MCO3 = 0.887HO2 + 0.747CH2O + 0.453MVK + 0.294MACR + 0.140HC5 + 0.113DIBOO + CO2 + MO2 1.68E-12 exp(500/T) Follow RIO2+NO without the yield of nitrate and NO2 and then rescale it.
68 HC5OO + MCO3 = 0.216GLYX + 0.234MGLY + 0.234GLYC + 0.216HAC + 0.29DHMOB + 0.17MOBA + 0.09RCHO + HO2 + 0.09CO + MO2 1.68E-12 exp(500/T) HC5OO=old IAO2, this radical channel use the same as HC5OO+NO without NO2 yield.
69 VRO2 + MCO3 = 0.4HO2 + 0.4CH2O + 0.6MCO3 + 0.6GLYC + 0.4MGLY + 1.0MO2 1.68E-12 exp(500/T) this radical channel use the same as VRO2+NO without NO2 and MVKN yield. And carbon balance.
70 MRO2 + MCO3 = 0.850HO2 + 0.143MGLY + 0.857HAC + 0.857CO + 0.143CH2O +1.0MO2 1.68E-12 exp(500/T) this radical channel use the same as MRO2+NO without NO2 and MACRN yield.
71 MAN2+MCO3 = MO2 +.5NO2+.5CH2O+.5MGLY+.5PROPNN+.5CO+.5HO2 1.68E-12 exp(500/T)
72 ATO2 +MCO3 =MGLY+ACTA 1.87E-13exp(500/T) IUPAC06 replace MEK with MGLY
73 HC5OO+MCO3 = MEK +ACTA 1.87E-13 exp(500/T)
74 ISOPNB + O3 = 0.610MVKN + 0.390MACRN + 0.27OH + CH2O 1.06E-16 Lockwood et al., 2010 ACP use 1,2 for beta channel
75 ISOPND + O3 = 0.5PROPNN + 0.5ETHLN + 0.27OH + 0.5GLYC + 0.5HAC 5.3E-17 Lockwood et al., 2010 ACP use 1,4 for delta channel
76 HC5+OH=HC5OO 3.35E-11exp(380/T) Paulot 2009a
77 HC5OO + NO = NO2 + 0.216GLYX + 0.234MGLY + 0.234GLYC + 0.216HAC + 0.290DHMOB + 0.170MOBA + 0.090RCHO + HO2 + 0.090CO K* (1-YN) where YN is returned from fyrno3.f K=2.7E-12 exp(350/T) (Xcarbn=4.00E00)
78 HC5OO +NO=HNO3 K* YN where YN is returned from fyrno3.f K=2.7E-12 exp(350/T) (Xcarbn=5.00E00)
79 HC5OO + HO2 = 0.1IAP + 0.9OH + 0.9MGLY + 0.9GLYC + 0.9HO2 2.91E-13*EXP(1300/T)[1-EXP(-0.245*n)], n=5 90% recycling, no experimental data. Somewhat based upon the high recycling rate observed for MVK/MACR
80 ISOPND+OH=ISOPNDO2 2.64E-11exp(380/T) Paulot 2009a
81 ISOPNB+OH=ISOPNBO2 3.61E-12exp(380/T) Paulot 2009a
82 ISOPNDO2 + NO = 0.070MACRN + 0.310HCOOH + 0.440HAC + 0.130ETHLN + 0.650CH2O + 1.340NO2 + 0.150GLYC + 0.310NO3 + 0.150PROPNN + 0.340MEK + 0.350HO2 K* (1-YN) where YN is returned from fyrno3.f K=2.7E-12 exp(350/T) (Xcarbn=4.00E00) Paulot 2009a
83 ISOPNDO2+NO=HNO3 K* YN where YN is returned from fyrno3.f K=2.7E-12 exp(350/T) (Xcarbn=5.00E00) Nitrates from ISOPND could not be observed in this experiment
84 ISOPNDO2 + HO2 = 0.035MACRN + 0.155HCOOH + 0.22HAC + 0.065ETHLN + 0.325CH2O + 0.170NO2 + 0.075GLYC + 0.155NO3 + 0.075PROPNN + 0.170MEK + 0.175HO2 + 0.5OH + 0.5ISNP 2.91E-13*EXP(1300/T)[1-EXP(-0.245*n)], n=5 Assume 50% recycling from HO2+RO2 (no experimental data - check Ng et al. for better estimates)
85 ISOPNBO2 + NO = 0.6GLYC + 0.6HAC + 0.4CH2O + 1.6NO2 + 0.26MACRN + 0.4HO2 + 0.14MVKN K* (1-YN) where YN is returned from fyrno3.f K=2.7E-12 exp(350/T) (Xcarbn=4.00E00) Paulot 2009a
86 ISOPNBO2 + NO = HNO3 K* YN where YN is returned from fyrno3.f K=2.7E-12 exp(350/T) (Xcarbn=5.00E00) Nitrates from ISOPND could not be observed in this experiment
87 ISOPNBO2 + HO2 = 0.3GLYC + 0.3HAC + 0.2CH2O + 0.13MACRN + 0.07MVKN + 0.3NO2 + 0.2HO2 + 0.5OH + 0.5ISNP 2.91E-13*EXP(1300/T)[1-EXP(-0.245*n)], n=5 Assume 50% recycling from HO2+RO2 (no experimental data - check Ng et al. for better estimates)
88 ISNP+OH=0.612OH+0.612R4N1++0.193ISOPNBO2+0.193ISOPNDO2 4.75E-12exp(200/T) replace the old ISNP+OH
89 MVKN+OH=0.650HCOOH+NO3+0.650MGLY+0.350CH2O+0.350PYAC 1.5E-12exp(380/T) Paulot 2009a
90 MACRN + OH = 1.0MACRNO2 1.39E-11exp(380/T)
91 MACRNO2 + NO = 0.08ACTA + 0.08CH2O + 0.15NO3 + 0.07HCOOH + 0.070MGLY + 0.850HAC + 0.85NO2 + 0.93CO2 + 1.0NO2 2.7E-12exp(350/T) no nitrate yield (acyl)
92 MACRNO2 + HO2 = 0.08ACTA + 0.08CH2O + 0.15NO3 + 0.07HCOOH + 0.07MGLY + 0.85HAC + 0.85NO2 + 0.93CO2 + 1.0OH 2.91E-13*EXP(1300/T)[1-EXP(-0.245*n)], n=4 Assume 100% recycling. No experiment data. Inferred from the very high recycling observed for MAO2+HO2
93 MACRNO2 + NO2=1.0PMNN LPL: 9.00E-28(300/T)^8.9 HPL:7.70E-12(300/T)^0.2 Fc: 0.6
94 PMNN =1.000MACRNO2 +1.000NO2 9e-29*exp(14000/T)
95 DHMOB + OH = 1.5CO + 1.0HO2 + 0.5HAC + 0.5MEK 2.52E-11exp(410/T)
96 DIBOO +NO=HO2+NO2+0.520GLYC +0.520MGLY +0.480HAC+0.480GLYX K* (1-YN) where YN is returned from fyrno3.f K=2.7E-12 exp(350/T) (Xcarbn=4.00E00) Dibble, 2004 Note that the yield of DIBOO Is likely overestimate (~30%)
97 DIBOO +NO=HNO3 K* YN where YN is returned from fyrno3.f K=2.7E-12 exp(350/T) (Xcarbn=5.00E00)
98 DIBOO + HO2 = 0.15HO2 + 0.15OH + 0.078GLYC + 0.078MGLY + 0.072HAC + 0.072GLYX + 0.85R4P 2.91E-13*EXP(1300/T)[1-EXP(-0.245*n)], n=5 Assume 100% recycling. No experimental data. Somewhat derived from the high recycling in MVK/MACR
99 MOBA +OH=MOBAOO 2.79E-11exp(380/T)
100 MOBAOO+NO=RCHO+CO2+HO2+NO2 K* (1-YN) where YN is returned from fyrno3.f K=2.7E-12 exp(350/T) (Xcarbn=4.00E00)
101 MOBAOO+NO=HNO3 K* YN where YN is returned from fyrno3.f K=2.7E-12 exp(350/T) (Xcarbn=5.00E00)
102 MOBAOO+HO2=0.500OH+0.500HO2+0.500RCHO+0.500CO2+0.500R4P 2.91E-13*EXP(1300/T)[1-EXP(-0.245*n)], n=5 Paulot 2009a No experimental constraint. Assume 50% recycling and go to R4P for the peroxide channel to avoid carrying another peroxide
103 MOBA +O3=OH +HO2+CO2+MEK 2.00E-17 Paulot 2009a Weak constraint on the rate constant - no constraint on the products
104 ETHLN +OH=CH2O +CO2+NO2 1.00E-11
105 PROPNN+OH=NO2+MGLY 1.00E-15 Paulot 2009a IUPAC says < 1e-12;Experiment suggests it is slower than than 1e-13-1e-15
106 RIO2 = 2.0HO2 + 1.0CH2O + 0.5MGLY + 0.5GLYC + 0.5GLYX + 0.5GLYX + 0.500HAC + 1.0OH 4.07E+08 exp(-7694/T) Peeters et al. (2009, 2010) Isomerization rate is adjusted according to Crounse et al. (2010), products follow Stavrakou et al. (2010).
107 MRO2 = 1.0CO + 1.0HAC + 1.0OH 2.90E+07 exp(-5297/T) Crounse et al. (2012) 1,4-H-shift isomerization rate dominates over 1,5-H-shift.
108 ISOP + O3 = 0.244MVK + 0.325MACR + 0.845CH2O + 0.110H2O2 + 0.522CO + 0.204HCOOH + 0.199MCO3 + 0.026HO2 + 0.270OH + 0.128PRPE + 0.051MO2 1.00E-14 *EXP(-1970/T) MCM v3.2 rate is from JPL 11, products from MCM, assuming CH2OO is dominated by reactions with H2O. ISOP + O3 in standard chem is not carbon-balanced.
109 MVK + O3 = 0.202OH + 0.202HO2 + 0.352HCOOH + 0.535CO + 0.050ALD2 + 0.950MGLY + 0.050CH2O 8.5 E-16exp(-1520/T) MCM? Rate is from IUPAC06
110 MACR + O3 = 0.261OH + 0.202HO2 + 0.326HCOOH + 0.569CO + 0.880MGLY + 0.120CH2O 1.4 E-15exp(-2100/T) MCM?
Photolysis RIP = OH + HO2 + 0.710CH2O + 0.425MVK + 0.285MACR + 0.29HC5
Photolysis MACRN=NO2+HAC+MGLY+0.500CH2O+HO2+0.500CO
Photolysis MVKN=GLYC +NO2+MCO3
Photolysis ISOPNB=HC5+NO2+HO2
Photolysis ISOPND=HC5+NO2+HO2
Photolysis PROPNN=CH2O +NO2+CO +MO2
Photolysis ATOOH=OH +CH2O +MCO3

RIP+OH

Follow SAR rules assuming a C(OOH) = 2* C(OH) = 7 (for the abstraction of the H alpha of the peroxide group). (see Kwok 1995 paper)

Assume that the abstraction of the peroxide H has a constant rate @298K of 3.6e-12

This gives for RIP:

43% 3.6e-12 (1,2)
28% 3.6e-12+7*1.94e-12 (4,3)
29% 3.6e-12+7*0.937e-12 (1,4)+(4,1) (I neglected 3,4 and 2,1)
9.3e-12@298K (4.75e-12*exp(200/T))
0.387 not recycling

Therefore 0.387=3.6/9.3. RIP + OH = 0.387RIO2 + 0.613OH + 0.613HC5.

Update One - RO2+HO2 Reaction Rate

Update applied to all >C2 RO2 species reaction with HO2. These include, in the standard scheme, R4O2, R4N1, KO2, RIO2, RIO1, IAO2,ISN1, VRO2, MRO2, MVN2, MAN2, B3O2, INO2, PRN1, A3O2, PO2.

Old RO2+HO2 reaction rate: k = 7.40E-13*EXP(700/T)

New RO2+HO2 reaction rate: k = 2.91E-13*EXP(1300/T)[1-EXP(-0.245*n)], where n=no. of carbon atoms

Comparison of new and old RO2+HO2 reaction rates for C4 RO2 and C5 RO2:

Ro2 ho2 rate.jpg

Benchmarking for this update can be viewed at: (Benchmarking results for RO2+HO2 reaction)

Update Two - Transport of RIP

RIP = isoprene peroxide species formed at low-NOx (i.e. via the RO2+HO2 pathway)

This benchmark is done to understand the muted influence of the increased rate of the RO2+HO2 reaction on CH2O. Is this because the ultimate yield of CH2O is similar for all levels of NOx and RIP is not transported, leading to the realization of the ultimate yield of CH2O in the same grid box as its emission source?

Both schemes are run with initial concentrations of species set to zero. As RIP is added as an additional transported species this was viewed as the most effective way of comparing the two model runs.

Benchmarking for this update can be viewed at: (Benchmarking results for transporting RIP)

Updates 02/04/2013

Old reaction Old rate New reaction New rate Note
KO2+HO2 =OH +ALD2 +MCO3 7.40E-13 exp(700/T) KO2 + HO2 = 0.15OH +0.15ALD2 +0.15 MCO3 + 0.85 ATOOH 2.91E-13*EXP(1300/T)[1-EXP(-0.245*n)], n=4 Assuming 15% recycling of OH, consistent with MCM. Rate is also from Saunders et al. (2003).
MRO2 +HO2 =0.020MRP+0.980OH +0.980HO2+0.294CH2O+0.686HAC +0.294MGLY +0.686CO 7.40E-13 exp(700/T) MRO2 + HO2 = 1.0MRP 2.91E-13*EXP(1300/T)[1-EXP(-0.245*n)], n=4 Isomerization of MRO2 is already taken into account in another reaction.
MAN2 + HO2 = 0.5PROPNN + 0.5CO + 0.5HO2 + 0.5MGLY + 0.5CH2O + 0.5NO2 + OH 7.40E-13 exp(700/T) MAN2 + HO2 = 0.075PROPNN + 0.075CO + 0.075HO2 + 0.075MGLY + 0.075CH2O + 0.075NO2 + 0.15OH + 0.85ISNP 2.91E-13*EXP(1300/T)[1-EXP(-0.245*n)], n=4 assuming 15% recycling
INO2 + HO2 = 0.5INPN + 0.5ISOPND + 0.5OH + 0.5HO2 7.40E-13 exp(700/T) INO2 + HO2 = INPN 2.91E-13*EXP(1300/T)[1-EXP(-0.245*n)], n=5 See nighttime chemistry
MAO3 + HO2 = 0.87OH +0.03O3 + 0.435CH2O + 0.435MO2 + 0.1MAOP + 0.030RCOOH + 0.283HAC + 0.152ATO2 + 0.870CO2 + 0.435CO 4.3E-13exp(1040/T) MAO3 + HO2 = 0.44OH +0.15O3 + 0.59CH2O + 0.39MO2 + 0.41MAOP + 0.39CO 4.3E-13exp(1040/T) use MCM, 44% OH channel, 15% O3 channel, 41% peroxide channel.
PMN + OH = 1.000PMNO2 3.20E-11 PMN + OH = HAC + CO + NO2 2.90E-11 from MCM
PMNO2 + NO = 0.6CO2 + 0.6HAC + 0.6NO3 + 0.4CH2O + 0.4HO2 + 0.4PYPAN + 0.900NO2 K* (1-YN) where YN isreturned from fyrno3.f; K=2.7E-12 exp(350/T) (Xcarbn=4.0E00) we now remove all reactions from PMN following MCM.
PMNO2 + NO=PMNN K* YN where YN is returned from fyrno3.f ; K=2.7E-12 exp(350/T) (Xcarbn=4.0E00)
PMNO2 + HO2 = 0.6CO2 + 0.6HAC + 0.6NO3 + 0.4CH2O + 0.4HO2 + 0.4PYPAN + 0.5R4P + 0.5OH 7.4E-13exp(700/T)
PYPO2 + NO2 + M = PYPAN LPL: 9.0E-28(300/T)^8.9 HPL:7.70E-12(300/T)^0.2 Fc: 0.6
PYPAN =PYPO2 +NO2 9.0E-29exp(14000/T)
PYPO2 + NO = CO2+MCO3 +NO2 2.7E-12 exp(350/T)
PYPO2 + HO2 = CO2+MCO3 +OH 7.40E-13 exp(700/T)
PYPAN = 0.300NO3+0.700NO2+MCO3 +CO2 photolysis
PYPAN = NO3 + MCO3 + CO2 photolysis
PP+OH=0.791OH+0.209PO2+0.791RCHO 8.78E-12exp(200/T) PP+OH=0.791OH+0.209PO2+0.791HAC
INPN+OH= 1.0OH + 1.0NO2 + 1.0MEK 1.9E-11exp(390/T) Now replaced by new nighttime chemistry
INPN+OH=0.36INO2+0.64R4N2+0.64OH 5.18E-12exp(200/T) Now replaced by new nighttime chemistry
DIBOO+HO2 = HO2 + OH + 0.52GLYC + 0.52MGLY + 0.48HAC + 0.48GLYX 7.4E-13exp(700/T) DIBOO + HO2 = 0.15HO2 + 0.15OH + 0.078GLYC + 0.078MGLY + 0.072HAC + 0.072GLYX + 0.85R4P 2.91E-13*EXP(1300/T)[1-EXP(-0.245*n)], n=5 assume 15% recycling of OH, rest goes to R4P
MOBAOO + HO2 = 0.5OH + 0.5HO2 + 0.5RCHO + 0.5CO2 + 0.5R4P 7.4E-13exp(700/T) MOBAOO + HO2=0.15OH + 0.15HO2 + 0.15RCHO + 0.15CO2 + 0.85R4P 2.91E-13*EXP(1300/T)[1-EXP(-0.245*n)], n=5 assume 15% recycling of OH, rest goes to R4P

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