Transcript РЕГИСТРАЦИЯ КОЛЕБАТЕЛЬНО

RECENT STUDIES OF OXYGENIODINE LASER KINETICS
Azyazov V.N. and Pichugin S.Yu.
P.N. Lebedev Physical Institute,Samara Branch, Russia
Heaven M.C.
Emory University, Atlanta, USA
Chemical OIL (COIL)
Cl2+НО2-HCl + Cl-+О2(1 )
PО2 100 Тор,
=[О2(1)]/[O2]50 %
О2
Nozzle
+
О2
О2(1 ), О
-
Resonator
Discharge OIL (DOIL)
О2(Х) + е  О2(1 ) + е
PО2 10 Тор,
  20 %
NO2 I2
UV photolysis
O3-SF6-N2O
О2(а1 )-O(1D)-I2(или CH3I)
Photolytic OIL (PhOIL)
О3 + hv  О2(1 ) + O(1D)
PО2 1 Тор,
  90 %
ENERGY
LEVELS OF I, O2, I2, H2O
List of reactions that of importance in the DOIL and PhOIL
Process
#
Rate constant, cm3 s-1
O2(1) formation
1
O2(3) + e  O2(1) + e
EE energy exchange
2
3
O2(1) + I(2P3/2)  O2(3) + I(2P1/2)
O2(3) + I(2P1/2)  O2(1) + I(2P3/2)
7.8×10-11
2.6×10-11
I atoms formation
4
5
I2(X) + O(3P)  IO+ I(2P3/2)
IO
+ O(3P)  O2(3) + I(2P3/2)
1.4×10-10
1.5×10-10
I(2P1/2) quenching
6
7
8
9
10
11
I(2P1/2) + O2(1)  I(2P3/2) + O2(1)
I(2P1/2) + I2(X)  I(2P3/2) + I2(X)
I(2P1/2)+ O(3P)  I(2P3/2) + O(3P)
I(2P1/2)+ O3
 products
2
I( P1/2)+ NO2, N2O4  I(2P3/2) + NO2, N2O4
I(2P1/2)+ N2O  I(2P3/2) + N2O
1.1×10-13
3.8×10-11
?
?
?
К(Т)?
O3 formation
12
13
14
O2 + O2 + O(3P)  O3 + O2
O(3P) + O(3P) + O2  O3 + O(3P)
O(3P) + O2 + Ar  O3 + Ar
5.9×10-34 cm6/s
5.9×10-34 cm6/s
5.9×10-34 cm6/s
O3 removal
15
16
17
I(2P3/2) + O3  IO + O2
O2(1) + O3  O2 + O2 + O(3P)
O2(1) + O3  O2(1) + O3
1.210-12
1.510-11
3.310-12
18
IO
19
 O2 + 2 I(2P3/2)
 IO2 + I(2P3/2)
IO + IO + M  I2O2 + M
8×10-12
3.2×10-11
5.6×10-30 cm6/s
O2(a1) quenching
20
O2(1) +O(3P) + O2  2O2 + O(3P)
?
O(3P) scavenge
21
O(3P) + NO2  O2 + NO
IO +IO reaction
+ IO
9.710-12
The low-pressure flow cell
apparatus with a jet-type SOG
Dependence of the I* concentration
on the distance along the flow for
w=3 %, O2:N2=1:1
Testing role of O2(1) by addition of CO2
Reducing [O2(1)] by an order of magnitude caused
a slight increasing of the dissociation time
O2(1)
I*
CO2:O2=0,92:1, P =2 Torr
c
CO2:O2=1,4:1, P =2,4 Torr
c
CO2:O2=1,84:1, P =2,8 Torr
c
14
0,4
-3
1.5
CO2:O2=2,3:1, P =3,2 Torr
Nb, 10 cm
c
14
NI* , 10 cm
-3
CO2:O2=2,8:1, P =3,7 Torr
c
1.0
0,2
CO2:O2=0,92:1, Pc=2 Torr
CO2:O2=1,4:1, P =2,4 Torr
c
CO2:O2=1,84:1, P =2,8 Torr
0.5
c
CO2:O2=2,3:1, Pc=3,2 Torr
CO2:O2=2,8:1, Pc=3,7 Torr
0.0
0,0
0
5
10
15
L, cm
0
5
10
15
20
L, cm
Quenching of O2(1) has a minimal effect
on the I2 dissociation rate
Role of I2(B) in the iodine dissociation
COIL active medium luminescence spectra
in the visible range recorded with a resolution
of 1 nm at Pc = 2.3 Torr, I2 =0.5%, N2:O2=1:1
718
I B X

I b X
 B Xdλ
480
768
 21.8
 b Xdλ
758
I B X
[I (B)]GB
 2
Ib X
[(O 2 (b)]Gb
GB=5105 s-1 , Gb=0.08 s-1
I B X
[I 2 (B)] 
[O 2 (b)]  (1.6  10 7 )  3.8  108 cm  3
Ib  X
Branching fraction
I2(A, A') + O2(a)  I2(1Π1u) + O2(X)  I + I + O2(X),
 I2(B) + M  I + I + M,
approx=100 %
<1%
Estimation of excitation probabilities
from Barnault et al. measurements
I*+ I2 I+I2(X,v)
v -excitation probability of v-th
vibrational level
n
v
Gm≤v≤n= v
m
Gv250.1
G10<v230.9 (0 for dashed curve)
Standard dissociation model with Gv25 0.1 can not provide observed
dissociation rates in COIL medium. About 20 molecules of O2(a)
consumed to dissociate one I2 molecule if standard model is
predominant dissociation pathway.
Pump-probe technique used to study OIL kinetics
Nd/YAG Pumped
Dye Laser
Quenching gas
I2+Ar
Monochro
mator
Ge
Digital
Oscilloscope
Delay
Generator
Pump
Fluorescence cell
Excimer laser
Light baffles
5
Rate of I2(A') quenching (Rq) depends on CO2
partial pressure РСО2 at PAr=50 Torr, РI2=0.013 Torr
and T=300 K
R q, s
-1
2x10
1x10
5
PCO2 , Torr
0
1
2
3
4
5
KCO2 = 8.510-13 cm3/s
KAr = 2.710-14 cm3/s
KO2 = 6 10-12 cm3/s
KI2 = 4.810-11 cm3/s
Branching fraction for O2(1) from O(1D)+N2O & O(3P)+N2O
N2O,NO2 or O3
O2(1) formation:
N2O +193 nm  O(1D) + N2
O(1D) + N2O  N2 + O2(1) ?
O(3P) + NO2  NO + O2(1) ?
Power
meter
1268 nm
filter
Ge photodetector
Pump
O3 +248 nm  O(1D) + O2(1)
O2(1)  O2(3)+1268 nm
 ,a  3.08
I, mV
E 248 I N 2O
E193 I O 3
1,0
Luminescence of O + NO reaction
at time< 0.2 msec
IO3
0,5
IN2O
IO3 mV
#
IN2O
mV
1
2
3
4
5
0.15
0.15
0.14
0.14
0.11
0.35
0.35
0.33
0.51
0.33
E193
E248
mJ
mJ
14.4
15.8
14.2
16
11
11.2
11.2
11.2
18.4
11.2
,a
1.03
0.94
1.03
0.97
1.05
Time, msec
0,0
Yield
0,0
0,5
1,0
1,5
Typical temporal profiles of the 1268 nm emission
intensities for the N2O photolysis experiment (IN2O) –
PN2O=207 Torr, PAr=407 Torr and for the O3 photolysis
experiment (IO3)- PN2=755 Torr, PAr=1.3 Torr
O(1D) + N2O  N2 + O2(1)
O(3P) + NO2  NO + O2(1)
100 %
<10 %
 N2 + O(1D)
 N2 + O2(1)
 NO + NO
O3 +248 nm  O(1D) + O2(1)
O(1D) + CO2(N2)  O(3P) + CO2(N2)
I2(X) + O(3P)  IO+ I(2P3/2)
IO + O(3P)  O2(3) +I(2P3/2)
I(2P3/2) + O2(1)  I(2P1/2) + O2(3)
I(2P1/2) + O(3P)  I(2P3/2) +О(3P)
I(2P1/2) + O3
 products
N2O + 193 нм
O(1D) + N2O
Emission intensity of I*, mV
Quenching I(2P1/2) by О(3Р), О3
3
PCO2=33,3 Torr
2
16,7 Torr
1
8,3 Torr
0
0,0
0,2
)
I(2P3/2
0,6
Time, msec
PO3/Torr
0.02
0.55
I(2P1/2
0,4
=248 nm
2
E=22 mJ/cm
)+ h (= 1315 nm)
0.33
Dashed lines are calculations at
KO=1.210-11 cm3/s
KO3=1.810-12 cm3/s
0.01
0.22
0.13
0.067
0.00
0.0000
0.0001
Time, sec
Quenching I(2P1/2) by NO2, N2O4 & N2O
CF3I + h (248 nm)  CF3 + I(2P1/2) sNO2=2.85x10-19 cm2
NO2 + h (248 nm)  O + NO
sNO2=2x10-20 cm2
N2O4 + h (248 nm)  NO2+ NO2
sN2O4= 80sNO2
 O+ NO+NO2
KN2O4= (3.70.5)×10-13 cm3/s
KNO2= (2.90.3)×10-15 cm3/s
KN2O= (1.30.1)×10-15 cm3/s
Quenching of O2(a1) in the presence О2 and O(3P)
O(3P) + O2(1) + O2  O(3P) + 2O2
Emisson intensity at 268 nm
PAr=92 Torr, PO2=680 Torr
0,0015
PAr=200 Torr, PO2=573 Torr
PAr=250Torr, PO2 =521 Torr
calcul.
calcul.
calcul.
calcul.
0,0010
Temporal emission intensity of
O2(1) at PO3=2.4 Torr, Ptot=773
Torr. Dashed lines are calculations at
K=1.1x10-31 cm6/s.
0,0005
t, sec
0,0000
0
Emission intensity at 600 nm
O3 +h(248 nm)  O(1D) + O2(1)
 O(3P) + O2(X)
O2(1)  O2(3)+ h (1268 nm)
PAr=305 Torr, PO2=467 Torr
20
40
60
80
PAr= 0 Torr, PO2= 762 Torr
PAr= 108 Torr, PO2= 654Torr
PAr= 249 Torr, PO2= 513 Torr
calcul.
calcul.
calcul.
0,001
t, sec
0,000
0
20
40
60
80
NO2 emission intensity near to
600 nm at PO3=2.4 Torr,
PN2O=2.8 Torr, Ptot=762 Torr
Conclusions
The total excitation probabilities of I2(X,v) in
reaction I* + I2  I + I2(X,v>10) are Gv25  0.1 and
G10<v<25  0.9
Standard dissociation model with Gv25 0.1 can not
provide observed dissociation rates in COIL medium.
About 20 molecules of O2(a) consumed to dissociate
one I2 molecule if standard model is predominant
dissociation pathway.
I2(B) and takes a minor part in iodine dissociation and
O2(b) does not play a noticeable role in I2(B) formation
I2 dissociation pathway involving O2(b) state is not
major channel
Conclusions
 Measured kinetic constants:
I2(A) + CO2 I2(X) + CO2
I2(A) + O2 I2(X) + O2
I2(A) + I2 I2(X) + I2
I2(A) + Ar I2(X) + Ar
О2(b) + CO2 О2(а) + CO2
О2(b) + O3 products
I(2P1/2) + O(3P)  I + O(3P)
I(2P1/2) + O3  products
I(2P1/2) + NO2  I + NO2
I(2P1/2) + N2O4  I + N2O4
I(2P1/2) + N2O  I + N2 O
O2(a1) + O(3P) + O2  O(3P) + 2O2
 Yield of O2(a1) in reactions
O(1D) + N2O  N2 + O2(3) or O2(1)
O(3P or 1D) + NO2 NО + O2(3) or O2(1)
(8.50.9)10-13 cm3/s
(6.00.6)10-12 cm3/s
(4.80.9)10-11 cm3/s
(2.70.3)10-14 cm3/s
(6.10.5)10-13 cm3/s
(1.90.2)10-11 cm3/s
(1.2±0.1)10-11 cm3/s
(1.8±0.4)10-12 cm3/s
(2.9±0.3)10-15 cm3/s
(3.7±0.5)10-13 cm3/s
(1.3±0.1)10-15 cm3/s
(1.1±0.2)10-31 cm6/s
-
1±0.12
< 0.1
Developed I2 dissociation model
O2(a,v=1)+I2(X)O2(X)+I2(A’)
O2(a,v=2)+I2(X)O2(X)+I2(A)
O2(a)+I2(A’,A)  O2(X)+2I
(95)
(96)
(25)
I* + I2  I + I2(10<v<25)
(33)
I2(10<v<25)+O2(a)O2(X)+I2(A’,A) (101)
O2(a,v=3)+I2(X)O2(X)+2I
(97)
O2(a,v=1)+I2(X,v15)O2(X)+2I (102)
O2(a,v=2)+I2(X,v8) O2(X)+2I (103)
O2(b) + I2(X)  O2(X) + 2I
(21)
Heidner et al. model
O2(a)+I2(X)O2(X)+ I2(20<v<45) (32)
I2(20<v<45)+O2(a)O2(X)+2I
(34)
I* + I2  I + I2(25<v<45)
(33)
Potential energy curves of I2. The red and blue arrows show
the excitation pathways of energy states lying bellow and
above the I2 dissociation limit, respectively. The inscriptions
above arrows denote the reaction producing excitation
Conclusions
A model that involves excitation of I2(A’,A) by
reactions
O2(a,v=1)+I2(X)O2(X)+I2(A’)
(95)
O2(a,v=2)+I2(X)O2(X)+I2(A)
(96)
O2(a)+I2(A’,A)  O2(X)+2I
(25)
I* + I2  I + I2(10<v<25)
(33)
I2(10<v<25)+O2(a)O2(X)+I2(A’,A)
(101)
yields results that are in reasonable
agreement with the flow tube experiments.