BROADENING OF MERCURY 2537-~ LINE IN THE PRESENCE OF CERTAIN METAL VAPORS

G. I. Zav'yalov, A. Yu. Zav'yalova, N. A. Prilezhaeva, M. P. Belyaev, M. V. Gileva, and V. S. Gmdanov

Izvestiya VUZ. Fizika, Vol. 11, No. 8, pp. 156-158, 1968

UDC 669.018:N35

EXPERIMENTAL

The investigation was carried out by an absorption method. The concentration of absorbing mercury atoms was achieved by introducing into a quartz tube a specific quantity of mercury, which was placed in the tube in ampuls before the tube was sealed off from the vacuum apparatus. The tube was degassed by strong heating with an oxygen flame during continuous evacuation. A vacuum of ~10 -4 mm was maintained in the tube at the moment when it was sealed off from the vacuum apparatus. High-purity cadmium, arsenic-free zinc, and pure magnesium were used in the experiments. The required extra- neous gas pressure (cadmium, zinc, and magnesium vapor) was given by the temperature of the branch tube. The temperatures of the branch and the tube were determined by means of platinum/platinum-rhodium thermocouples. The light source was a DKSSh-1000 lamp giving a continuous spectrum in the ultraviolet region. The spectra were photo- graphed by means of an ISP-28 spectrograph using "Spectrographic Type 2" plates. The exposure varied between 5 and 80 rain. Before recording the spectra the tube was maintained at the required temper- ature for 2 hr. The absorption spectra were recorded with various tem- perature conditions in the tube between 680 and 960" C. The concen- tration of memury atoms in the tube in this temperature range varied between 9.1.10 "~6 and 9 ~ 10 -16 cm -3, which was taken into account when the results were analyzed. The spectra were analyzed by photo- graphic photometry.

RESULTS AND DISCUSSION

In the absorption spectra of mercury vapor with cadmium, zinc, and magnesium vapors, and a mercury atom concentration of ~10 l~ cm -s, the Hg 2587-~ resonance line showed a small degree of broad- ening. From Fig. 1 it is seen that, for this case, fKvdzs does not de- pend on the temperature of the tube, with the branch temperature constant. The same feature was observed with this absorption line in [~-3].

With a mercury atom concentration of 9. I0 z6 cm -s and with

the same vapor pressures for cadmium and zinc, considerable broaden-

ing was found in the Hg-259?-A line. Under our conditions the line

extended altogether (within the limits of appreciable intensity) from

250 cm -i to 400 cm -~, The contours of the 2587-~ line for (Hg + Cd)

and (Hg+ Zn) vapors are distinctly asymmetrical. The asymmetry of

the mercury absorption line contours was determined by the ratio U of

the areaS I, bounded by the long-wave portion of the contour, to the

area S s, bounded by the short-wave portion. In both cases there is red

asymmetry, for which U ~ 3. When the pressure of the extraneous gas (Cd, Zn) is increased fKvdv increases, and the extent of the absorp- tion line shows little change. In the long-wave portion of the line there is a gradual drop in intensity and slight fluctuations. As seen

$/i'vdr

g g

- o _ ~ - e . . . o _

[8 107J 1173 1273 r

Fig. 1: Dependence of f Kvdu-on tube temperature. O ) f o r ( H g + Cd), ~ )for(Hg+ Zn), �9 ) for(Hg+

+ ~ g ) o . . . .

from Figs. 2 and 8, the dependence of fKvdv on the cadmium and zinc vapor pressures at constant temperature exhibits, to a satisfactory degree of approximation, a linear character. The possibility of in- creasing the vapor pressure was limited by the appearance of weak molecular absorption bands ("striation'). The molecular bands

( 's tr iat ion') arising from the appearance of Cdz and Znz molecules [4:-. 63 were not considered in the present work.

From Figs. 4 and 5 it is seen that, with increase in temperature, f Kvdv has a nonlinear temperature dependence. From curves similar to those shown in Fig. 6, it is seen that for a considerable part of the long-wave region of the Hg 2587-~ absorption line, the intensity dis- tribution I v ~ K v coincides with the Kuhn dislzibution [7] for the wing of the line K(v) ~ (v - Vo)a/2, arising from van der Waals forces with an interaction energy of ~e/r *. This leads to the conclusion that the formation of the long-wave portion in the Hg 2587-~ absorption line for the (Hg + Cd) and (Hg + Zn) systems is clues to tile statistical effect.

8//6d ~

40

/ 200 400 EO0 P

Fig. 2. Dependence of f K_udv on cadmium vapor

pressure (ram) at T = 1188 ~ K.

3K~ d~ 80

60

48; J

/ /

60O 8OO MOO P Fig. 3. Dependence of f Kudv on the zinc

vapor pressure (ram) at T = 1253 ~ K.

~IcydO i p..

6# ] J Y

/ ,o !

117d 1295 1273 IJY3 Y Fig. 4. Dependence of f Kvdu on the cube temperature at a zinc atom concentration

of 5_~- i01~ c m -~

97

M:vd~ ~0

.! / /

40 1 /, JO

,~TJ 975 /071 #7I r Fig. 5. Dependence of f Kvdu on the tube temperature at cadmium atom concentration

of-2.3.1019 cm -z.

I ' [ e �9 eV( 6v

Fig. 6. Dependence of logK u on log (v0 -- u) for the long-wave portion of the line contour.

O ) f o r ( H g + Cd), � 9 Zn).

On the basis of the results i t can be assumed that in the absorbing medium under the conditions of our experiments, with a mercury atom concentration of 9.1016 cm -a, in addition to vapors of (Hg + Cd) and (Hg + Zn) particles, which exist during collision, there are also (Hg + + Cd) and (Hg + Zn) quasi-molecules.

REFERENCES

1. T. Skalinski, Bull. Akad. Polon. Sci., 8, 119, 1960. 2. A. Yu. Zav'yalova, G. I. Zav'yalov, and N. A. Prilezhaeva,

Izv. Vuzov SSSR, Fizika, no. 5, 1964. 3. T. Crycuk, M. Kubiak, and I. Prochorow, Bull. Akad. Poion.

Sci., 12, 517, 1964. 4. H. Hamada, Phil. Mag., 12, 50, 1931. 5. S. W. Cram, Phys. Rev., 46, 205, 1984. 6. R. Pearce and A. Heydon, Interpretation of Molecular Spectra

[Russian translation], Moscow, 1949. 7. H. Kuhn, Phil. Mag., 18, 987, 1934. 8. Yu. A. Knshnikov, Izv. Akad. Nauk SSSR, Ser. Fiz., ~2, 366,

1948. 9. G. I. Zav'yalov and A. Yu. Zav'yalova, Izv. Vuzov SSSR:

Fizika, no. 4, 1961.

8 July 1967 Armavir Higher Aviation School

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