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Determination of the atomic-state densities of some energy levels in Ar−Br2 mixtures
I. Oc~t. Speamsc. P.adiaa. Transfer Vol. 23, pp. 237-240
0022.-4073/80~201-0237152.00/0
@ Peqlmom Press Ltd., 19BO. I~nted in Great Britain
NOTE DETERMINATION OF THE ATOMIC-STATE DENSITIES O F S O M E E N E R G Y L E V E L S IN Ar-Br2 M I X T U R E S V. HEN(~-BARTOLIC Faculty of Electrical Engineering, Zagreb, Yugoslavia
D. SOLDOand A. PER~IN Institute "Rudjer Bo~koviC', 41000 Zagreb, Yugoslavia
and M. Du~i Faculty of Mining-Metallurgical Engineering, Kosovska Mitrovica, Yugoslavia (Received 6 June 1979) Abstract--The atomic-state densities of the 4s Ar energy levels and 5s Br energy levels in Ar-Br2 mixtures have been determined as function of current strength. INTRODUCTION
We have determined the atomic-state densities of the 4s levels of Ar and 5s levels of Br in Ar-Bre mixtures. The partial energy diagrams of Ar and Br are shown in Fig. 1. This figure was Ar
Br E(eV)
E(eV) 13,
12,
11
r'P,c.,)| ?el'p,c..)t:: L'e.t.,)
10
"1~i)eo(s s) r-
5s' ~Ow~
"SP~O~n
~e.¢Pu2
10 ¸
OA 0
8' AE = I.g7ov,
0
3p* iS 0 A E - d i s ~ i n t i o n energy of Br2
Fig. i. Partial energy dia~ams of At(I) and Br(l).
V. HENt~-BARTOLI(~et al.
238 lJ
I
2.2 2.0 1.6
_ \\
1.6 1.4 1.2 1.0
t 1
I 2
I 3
i /4
k 0l
Fig. 2. Variationof kol with the flux ratio I'/I. drawn using data from Refs. 2-4. It is apparent that the 4s metastable levels of Ar appear at nearly the same energies as the 5p levels of Br if the energies of these Br-levels are increased by the dissociation energy, AE, of Br2. It may, therefore, be assumed that the transfer of excitation energy occurs between Ar-atoms in the metastable state and Br-molecules in the ground state/ MEASUREMENTS AND RESULTS The atomic-state densities in selected mixtures were determined using the self-absorption method described by McConkey. ''6 The discharge temperature T was approx. 300°K; it was obtained by measuring the Doppler half-width of the Ar line at 6965 ~, using a Fabry-Perot interferometer. Measurements were performed in Ar-Br2 mixtures at a partial Ar pressure of 0.2 torr and at a partial pressure of saturated Br2 vapors of ~ 0 and 0.03 torr. The light from sections of the positive column of the discharge (0 = 12 mm), of lengths ! and !', was analyzed (i' = 8.7 cm = 2.13 1). The values of kol (ko is the absorption coefficient) for the various flux ratios I ' / I were calculated following the method of Ref. 6 (Fig. 2). Measurements were performed for transitions from 417 to 4s states of Ar and for transitions from 5p to 5s states of a Br atom (Fig. 1). The absorption oscillator strengths of the transitions, i.e. the [-values for Ar and Br, were calculated by using transition probabilities found in the literature.
.I
Ar I x
!~, x
•
• x •
x
x,
9
x
x
•
.
, 9
x 9 9x
w v
~ 9
~
•
V * V v • V *
v
~
* 9
v ? * •
*~ v
,,,,,,,,,
x x
s
V v * *
x
~
9"
v
x
v
x
x
e, x x
~
• ;
*
;;vO::
'e,
5 'q Z
o
~ ÷o. s ÷
::~,,e
•
'r,
" . O *4,o o ' * o a ~ . ° :
p,, = 0 . 2 torr ph 2 ~, 0 torr
.~
5
$
•
T2
}t
HI
lip
~
22
~
21b
n
3o
l(mA)
Fig. 3. Variations of the ~P~,~Po,3Pt, and 3P2 state densities of Ar with current strength in an Ar--Br2 mixture with trace amounts of bromine; ©O©, + + +, AAA, AAA; VVV, I)1141, x x x, and ¥VV denote measurementsperformedusingthe 8521.4,8264.5,7948.2,7724.2,8103.7,8424.6,8115.3and 7635d ,~ Ar lines, respectively.
Determination of the atomic-state densities of some energy levels in Ar-Br: mixtures Ar
239
l
p,, -- 0.2 torr P"z = 0.03 torr X X X
x X
E LJ
•
X
x
X
X X
X
" v " v "
• •
x
9it
x
x
•
•
•
~
xv~ " '
~Pz
•
.:,::,1.,:.'" • ,, ,,.;; , ' , ; ' , ; - [..
•
•
~
•
.
.
•
~
.eg.vvvv
V V
v
•
P1
I tm~ Fig. 4. Variation of the *P,, ~Po, 3p,, and 3P2 state densities with current strength in an Ax-Br: mixture at a partial Br pressure of 0.03 torr.
8¢1 p,, = 0.2 tort • ~
pro,= 0.03 torr •
1"
*
••
• x
| •
!
|
t
e
.
:j:':::*':t,l::':t::'''**
'P,,~
I(mA) Fig. 5. Variations of the 2P312,"PII2 and 4P;I 2 Br state densities with current strength in an Ar-Br2 mixture at a partial Br pressure of 0.03 ton'; O C t , x x x, AAA, and ~ denote measurements performed using the 7348.5, 7005.2, 8131.5, and 8334.7 ~ Br lines, respectively.
The f-values thus determined for Ar are: 0.16(-+ 25%), 0.17( -+25%), ().56( -+ 20%), 0.34( _+ 20%), 0.27(_ 25%), 0.34( _+5%), 0.31(-+ 6%), and 0.26( _+ 11%) for the Ar lines at 8521.4, 8264.5, 7 7948.2, s 7724.2, s 8103.7, ~ 8424.6, 9 8115.3, 9"m°and 7635.1 A,m' respectively. The f values determined for Br are: 0.09 ( +_50%), 0.144( _+35%), 0.075( _+35%), 0.150( _+50%) for lines at 7005.2, 7348.5, 8131.5, and 8334.7 A, respectively} 2 Figures 3 and 4 show the atomic-state densities of the 4s levels of Ar as functions of current strength (3-30 mA). It is shown in these figures that the densities decrease with increasing partial pressure of Br. Figure 5 shows atomic-state densities of the 5s levels of Br, which are radiatively connected with the 5p levels of Br. These densities were measured in a mixture at a partial Br-pressure of 0.03 torr. The determinations of ko, T, and wavelength introduced a measuring error of approximately 10%. In view of known errors in the f values, which range from 5 to 25% for Ar and from 35 to 50% for Br, the overall errors in the population densities are between 15 and 35% and between 45 and 60%, respectively. REFERENCES I. A. Periin, V. Hen~-Bartoli~ and D. Sold•, JQSRT 15, 423 (1975). 2. C. E. Moore, "Atomic Energy Levels", Nat. Bur. Stand., Washington, D.C., U.S.A., Circ. 467, p. 159, Vol. ]l 0952). 3. A. R. S ~ v and N. S. Sventickij, Tab/ici sp~trainih Iinij nejtralnih i ionizovanih atom•v, p. 328. Atomizdat, Moskva (1966). 4. A. N. Zaidel, V. K. Prokofev, S. M. Raiskii, V. A. Slavnii, and E. J. Sreider, Tablici spetaralnih linij, pp. 362, 382. Nauka, Moskva (1969).
240
V. HEN~-BARTOLIt~et al.
5. C. K. N. Patel, R. A. McFarlane, and W. L. Faust, Phys. Rev. 133, 5A, AI244 (1964). 6. J. W. McConkey, J. Opt. Soc. Am. 59, 1262 0969). 7. W. L. Wiese, M. W. Smith, and B. M. Miles, "Atomic Transition Probabilities", Nat. Stand. Re[. Data Ser., Washington, D.C.U.S.A., Nat. Bur. Stand., 22, Vol. II (1969). 8. W. L. Wiese, 8th Int. Con[. Phenomena in Ionized Gases, Contributed Papers, p. 447. Springer-Verlag, Vienna (1967). 9. H. N. Olsen, JQSRT 3, 59 (1963). 10. L. R. Doherty, Thesis, University of Michigan, Ann. Arbor, Michigan (1%1). II. J. B. Shumaker, Jr., and C. H. Popenoe, J. Opt. Soc. Am. 57, 8 (1967). 12. R. D. Bengtson, M. H. Miller, D. W. Koopman, and T. D. Wilkerson, Phys. Rev. A3, 16 (1971).
0022.-4073/80~201-0237152.00/0
@ Peqlmom Press Ltd., 19BO. I~nted in Great Britain
NOTE DETERMINATION OF THE ATOMIC-STATE DENSITIES O F S O M E E N E R G Y L E V E L S IN Ar-Br2 M I X T U R E S V. HEN(~-BARTOLIC Faculty of Electrical Engineering, Zagreb, Yugoslavia
D. SOLDOand A. PER~IN Institute "Rudjer Bo~koviC', 41000 Zagreb, Yugoslavia
and M. Du~i Faculty of Mining-Metallurgical Engineering, Kosovska Mitrovica, Yugoslavia (Received 6 June 1979) Abstract--The atomic-state densities of the 4s Ar energy levels and 5s Br energy levels in Ar-Br2 mixtures have been determined as function of current strength. INTRODUCTION
We have determined the atomic-state densities of the 4s levels of Ar and 5s levels of Br in Ar-Bre mixtures. The partial energy diagrams of Ar and Br are shown in Fig. 1. This figure was Ar
Br E(eV)
E(eV) 13,
12,
11
r'P,c.,)| ?el'p,c..)t:: L'e.t.,)
10
"1~i)eo(s s) r-
5s' ~Ow~
"SP~O~n
~e.¢Pu2
10 ¸
OA 0
8' AE = I.g7ov,
0
3p* iS 0 A E - d i s ~ i n t i o n energy of Br2
Fig. i. Partial energy dia~ams of At(I) and Br(l).
V. HENt~-BARTOLI(~et al.
238 lJ
I
2.2 2.0 1.6
_ \\
1.6 1.4 1.2 1.0
t 1
I 2
I 3
i /4
k 0l
Fig. 2. Variationof kol with the flux ratio I'/I. drawn using data from Refs. 2-4. It is apparent that the 4s metastable levels of Ar appear at nearly the same energies as the 5p levels of Br if the energies of these Br-levels are increased by the dissociation energy, AE, of Br2. It may, therefore, be assumed that the transfer of excitation energy occurs between Ar-atoms in the metastable state and Br-molecules in the ground state/ MEASUREMENTS AND RESULTS The atomic-state densities in selected mixtures were determined using the self-absorption method described by McConkey. ''6 The discharge temperature T was approx. 300°K; it was obtained by measuring the Doppler half-width of the Ar line at 6965 ~, using a Fabry-Perot interferometer. Measurements were performed in Ar-Br2 mixtures at a partial Ar pressure of 0.2 torr and at a partial pressure of saturated Br2 vapors of ~ 0 and 0.03 torr. The light from sections of the positive column of the discharge (0 = 12 mm), of lengths ! and !', was analyzed (i' = 8.7 cm = 2.13 1). The values of kol (ko is the absorption coefficient) for the various flux ratios I ' / I were calculated following the method of Ref. 6 (Fig. 2). Measurements were performed for transitions from 417 to 4s states of Ar and for transitions from 5p to 5s states of a Br atom (Fig. 1). The absorption oscillator strengths of the transitions, i.e. the [-values for Ar and Br, were calculated by using transition probabilities found in the literature.
.I
Ar I x
!~, x
•
• x •
x
x,
9
x
x
•
.
, 9
x 9 9x
w v
~ 9
~
•
V * V v • V *
v
~
* 9
v ? * •
*~ v
,,,,,,,,,
x x
s
V v * *
x
~
9"
v
x
v
x
x
e, x x
~
• ;
*
;;vO::
'e,
5 'q Z
o
~ ÷o. s ÷
::~,,e
•
'r,
" . O *4,o o ' * o a ~ . ° :
p,, = 0 . 2 torr ph 2 ~, 0 torr
.~
5
$
•
T2
}t
HI
lip
~
22
~
21b
n
3o
l(mA)
Fig. 3. Variations of the ~P~,~Po,3Pt, and 3P2 state densities of Ar with current strength in an Ar--Br2 mixture with trace amounts of bromine; ©O©, + + +, AAA, AAA; VVV, I)1141, x x x, and ¥VV denote measurementsperformedusingthe 8521.4,8264.5,7948.2,7724.2,8103.7,8424.6,8115.3and 7635d ,~ Ar lines, respectively.
Determination of the atomic-state densities of some energy levels in Ar-Br: mixtures Ar
239
l
p,, -- 0.2 torr P"z = 0.03 torr X X X
x X
E LJ
•
X
x
X
X X
X
" v " v "
• •
x
9it
x
x
•
•
•
~
xv~ " '
~Pz
•
.:,::,1.,:.'" • ,, ,,.;; , ' , ; ' , ; - [..
•
•
~
•
.
.
•
~
.eg.vvvv
V V
v
•
P1
I tm~ Fig. 4. Variation of the *P,, ~Po, 3p,, and 3P2 state densities with current strength in an Ax-Br: mixture at a partial Br pressure of 0.03 torr.
8¢1 p,, = 0.2 tort • ~
pro,= 0.03 torr •
1"
*
••
• x
| •
!
|
t
e
.
:j:':::*':t,l::':t::'''**
'P,,~
I(mA) Fig. 5. Variations of the 2P312,"PII2 and 4P;I 2 Br state densities with current strength in an Ar-Br2 mixture at a partial Br pressure of 0.03 ton'; O C t , x x x, AAA, and ~ denote measurements performed using the 7348.5, 7005.2, 8131.5, and 8334.7 ~ Br lines, respectively.
The f-values thus determined for Ar are: 0.16(-+ 25%), 0.17( -+25%), ().56( -+ 20%), 0.34( _+ 20%), 0.27(_ 25%), 0.34( _+5%), 0.31(-+ 6%), and 0.26( _+ 11%) for the Ar lines at 8521.4, 8264.5, 7 7948.2, s 7724.2, s 8103.7, ~ 8424.6, 9 8115.3, 9"m°and 7635.1 A,m' respectively. The f values determined for Br are: 0.09 ( +_50%), 0.144( _+35%), 0.075( _+35%), 0.150( _+50%) for lines at 7005.2, 7348.5, 8131.5, and 8334.7 A, respectively} 2 Figures 3 and 4 show the atomic-state densities of the 4s levels of Ar as functions of current strength (3-30 mA). It is shown in these figures that the densities decrease with increasing partial pressure of Br. Figure 5 shows atomic-state densities of the 5s levels of Br, which are radiatively connected with the 5p levels of Br. These densities were measured in a mixture at a partial Br-pressure of 0.03 torr. The determinations of ko, T, and wavelength introduced a measuring error of approximately 10%. In view of known errors in the f values, which range from 5 to 25% for Ar and from 35 to 50% for Br, the overall errors in the population densities are between 15 and 35% and between 45 and 60%, respectively. REFERENCES I. A. Periin, V. Hen~-Bartoli~ and D. Sold•, JQSRT 15, 423 (1975). 2. C. E. Moore, "Atomic Energy Levels", Nat. Bur. Stand., Washington, D.C., U.S.A., Circ. 467, p. 159, Vol. ]l 0952). 3. A. R. S ~ v and N. S. Sventickij, Tab/ici sp~trainih Iinij nejtralnih i ionizovanih atom•v, p. 328. Atomizdat, Moskva (1966). 4. A. N. Zaidel, V. K. Prokofev, S. M. Raiskii, V. A. Slavnii, and E. J. Sreider, Tablici spetaralnih linij, pp. 362, 382. Nauka, Moskva (1969).
240
V. HEN~-BARTOLIt~et al.
5. C. K. N. Patel, R. A. McFarlane, and W. L. Faust, Phys. Rev. 133, 5A, AI244 (1964). 6. J. W. McConkey, J. Opt. Soc. Am. 59, 1262 0969). 7. W. L. Wiese, M. W. Smith, and B. M. Miles, "Atomic Transition Probabilities", Nat. Stand. Re[. Data Ser., Washington, D.C.U.S.A., Nat. Bur. Stand., 22, Vol. II (1969). 8. W. L. Wiese, 8th Int. Con[. Phenomena in Ionized Gases, Contributed Papers, p. 447. Springer-Verlag, Vienna (1967). 9. H. N. Olsen, JQSRT 3, 59 (1963). 10. L. R. Doherty, Thesis, University of Michigan, Ann. Arbor, Michigan (1%1). II. J. B. Shumaker, Jr., and C. H. Popenoe, J. Opt. Soc. Am. 57, 8 (1967). 12. R. D. Bengtson, M. H. Miller, D. W. Koopman, and T. D. Wilkerson, Phys. Rev. A3, 16 (1971).