Laboratory tests of infrared spectrum of carbon suboxide, to determine presence in Venus and Mars atmosphere

Cruikshank, D. P.

Fink, U.

Kuiper, G. P.

Sill, G. T.

English

NASA Technical Reports Server

. -  
! I \ %  
No. 99 THY INFRARED SPECTRUM OF CARBON SUBOXIDE 
PART I: REGION 1-2.5 MICRONS 
by G.  P. KUIPER, G. T. SILL (0. CARM.) AND D. P. CKUIKSHANK 
November 22,1967 
ABSTRACT 
Laboratory tests of the spectrum of C,O, in the region of 1-25 microns are presented in order to establish the most 
favorable tests for the presence of this gas on Venus and Mars. The results are shown in Figures 1 and 2. 
ne of the more interesting gases of which traces 0 may be present in the Venus atmosphere is car- 
bon suboxide, CSO:!. It will be poduced photochemi- 
cally in a mixture of carbon dioxide and carbon 
monoxide under the influence of several types of 
radiation (far ultraviolet, X-ray, electrms and pro- 
tons) so that traces must be produced in the upper 
atmosphere of Venus. Since its near-infrared spec- 
trum apparently has not been observed before, 
absorption spectra of the gas have been obtained in 
the lead-sulfide region. The gas was produced by one 
of us (G. S.) with the assistance of Dr. John Schaefer 
and Linda Honig of the University of Arizona De- 
partment of Chemistry. 
Diacetyl tartaric anhydride was produced by the 
acetylation of tartaric acid with acetic anhydride. The 
product was crystallized from solution, washed with 
benzene and dried in a vacuum dessicator over P205 
for 24 hrs. The intermediate, diacetyl tartaric an- 
hydride (CH3 COO):! C4HP03, was pyrolyzed zt 
680" C in a vycor pyrolysis tube to produce the car- 
bon suboxide and large amounts of byproduct, acetic 
acid and carbon monoxide. The acetic acid was first 
removed with a water condenser and the carbon sub- 
oxide collected in a dry-ice acetone trap at -78" C. 
The C301 was distilled at room temperature (B. P. 
7" C) and the distillate collected again in a dry-ice 
acetone trap. 
Two sets of records were obtained, one of which 
is reproduced in Figures 1 and 2. Both used a 39 cm 
cell placed between the filament source and a positive 
lens which made an image of the source on the spec- 
trometer slit in order that the collimator beam would 
be filled. For the first records, a small amount of C3O2 
gas was admitted to the tub-. but its pressure was not 
readily determined. In the i-cond set, the gas pres- 
sure was approximately 600 mm, in equilibrium with 
the CsOz liquid boiling in a water-and-ice bath at 
0" C. During the spectral runs some polymerization 
of the gas occurred on the walls of the cylindrical 
Pyrex tube, but it is not believed that the gas pres- 
sure was diminished drastically. No observable bands 
occurred in the interval 1 .O-2.5 y outside the inter- 
vals reproduced in Figures 1 and 2. The continuum 
in the figures was not normalized from the original 
recordings, but the approximate position of the un- 
disturbed level is indicated by the smooth lines added 
to the tracings. 
The classification of the higher overtones of C302 
is not readily made on the basis of the available 
literature (Herzberg 1945; Lafferty, Maki, and Plyer 
1963; Aleksandrov, Tyulin, and Tatevskii 1963, 
20 1 
https://ntrs.nasa.gov/search.jsp?R=19690003313 2020-03-12T08:10:08+00:00Z
202 G .  P. KIJIPER,  G .  T. SILL (0. C A R M . )  A N D  D .  P. CRUIKSHANK 
1.75 p 1.70 1.65 1.60 1.55 1.50 1 . 4 5 ~  I 
1 1 1 1 ~ 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ( 1 1 1 1 ~ 1 1 1 1 ~ 1 1 1 1  
"20 
I 
2 V l  + VJ 
Fig. 1 
U. Fink in Part 111. Straight lines suggest undisturbed continuum level. 
Absorption spectrum of 39 cm of C302 at p = 600 mm, 1.40 - 1.75 p, with classifications derived by 
to 
2.40 2.35 2.30 2.25 2.20P 2 
,/ 
/---- 
v, -I- v2 -I- V4 
0 
1 1 ,  I l l , ,  , I ,  . 1 1 0 1 , 1 l 1 1 1 1 1 1 1 1 1  
Absorption spectrum of 39 cm of Ca02 at p = 650 mm, 2.15 - 2.45 p ,  with classifications derived by Fig.2 
U. Fink in Part 111. Straight lines suggest undisturbed continiium level. 
 
5 
THE SPECTRUM O F  CARBON SUBOXIDE ON VENUS 203 
Table 1).  The assignments made in Figures 1 and 
2 are based on the abovc references and a study by 
Dr. Uwe Fink found in Part 111. 
TABLL: 1 
FUNDAMENTAL FREQUENCIES USED 
_.______ ____ ~ .~ ~ ~ _ _ _ _ _  
ASSIGNMENT DESIGNATION BAND C E N T E R ,  CM 1 kVAVEl.LNGlt1 (/I) 
4.5s 
12.05 
4.41 
Y1 UtK 2200 
1’2 U+L 830 
kl Ut“ 2270 
U4 U t ”  I570 6.37 
YS 7rL 580 17.24 
Yti n u  550 18.18 
Y7 7r” 63[190] 159[52.6] 
It is apparent that the most semitive test for the 
prcssure of CaOn on Venus within the spectral region 
considered is by means of the vl -k v3 band at 2.26 p 
(4440 cm-’). Fortunately, this region is free from 
strong CO, absorptions. 
Acknowledgments. The planetary program is 
supported by the National Aeronautics and Space 
Administration through Grant NsG 161-61. We are 
much indebted to Dr. Schaefer and Miss Linda 
Honig for their assistance with the production of 
thc C:,02 sample. 
REFERENCES 
Aleksandrov, A., Tyulin, V., and Tatevskii, V. 1963, 
“Vibration-1 Spectra of Carbon Suboxide (C,O*) 
in Different States of Aggregation,” Optics and 
Spectroscopy, 17 ( 11 ,  19-22. 
Herzberg, G. 1945, Molecular Spectra and Molecu- 
lar Structure, Vol. I1 in Infrared and Raman 
Spectra of  Polyatoinic Molecules (New York: 
D. Van Nostrand Co.). 
Lafferty, W., Maki, A., and Plyler, E. 1963, “High- 
Resolution Infrared Determination of the Struc- 
ture of Carbon Suboxide,” J. Chem. Phys., 40, 
For the Production of CaOr, cf. N. Habjohn, ed. 
1963, Organic Syiithesis (New York: John 
Wiley and Sons), Vol. IV p. 242; and C. D. 
Hurd and F. D. Pilgrim, 1933, Journ. Amer. 
Chem. SOC., 55,757. 
( 1 ), 224-229. 
ADDENDUM 
ULTRAVIOLET TEST FOR C302 IN THE VENUS ATMOSPHERE 
by D. P .  CRUIKSHANK A N D  G. T. SILL (0. CARM) 
n order to test the ultraviolet spectrum of Venus I far traces of C. 32, spectra of the sun in the region 
3 100--3600 A wcre obtained through an absorpt..on 
cell containing 35.1 cm-atm (at pressure 62.2 cm 
Hg) of the gas, Sunli. as reflected from a Mg3 
screen. As with the ult, . .olet test for SOz (Cruik- 
shank and Kuiper, 136‘7), a wide slit of 250 p, was 
used to soften the profiles of the numerous Fraun- 
hofer lines in this spectral region. Eastman 103a-0 
plates were used, and the dispersion was 8 A/mm. 
There were no detectable bands in our spectra of 
this small amount of Ca02. This is consistent with 
the results of ‘rhompson and Healcy (1936) who 
found that thc ban(ls in this spectral region begin to 
show with adout C .. in-atm of the gas. It follows that 
the in jrared jundaniental and overtone absorptions 
provide the most sensitive tests for the possible 
presence of carbon suboxide on Venus in the wave- 
length regions iccessible in ground-based or high- 
altitude airborne observations. 
We are grateful to Mr. Allen Thomson who 
assisted in obtaining the observations. 
REFERENCES 
Cruikshank, D. F, and Kuiper, G. P. 1967. “Upper 
Limits for the Abundance of SO2 on Venus.” 
Comm. LPL No. 97, 195-197. 
Thompson, H. W., and Healey, N. 1936, “The Spec- 
trum and Photochemistry of Carbon Suboxide,” 
Proc. Royal SOC. London, 157, 331-347. 
204 D. P. CRUIKSHANK A N D  G .  T S I L L  (0. C A X M . )  
PART 11: REGION 2-16 MICRONS 
by D. P. CRUIKSHANK AND G. T. SILL (0. CARM.) 
ABS'I KACT 
Two tracings of the infrared spectrum of C,O, are presented for estatlishing suitable tests for the presence of C,O, in 
planetary atmospheres. It is estimated that a strong blended band at 6.37 B (1570 cm-1) could be detected on Mars or Venus 
if prescnt in amoiints greater than 0.05 mm-atm. 
his paper extends the spectral observations of Tc. ,{ o to 15 p. Its purpos; is: (a) to find the strong- 
est absorption bands in the region 2-15 p accessible 
from high-altitude aircraft using modern detectors, 
and (b) to determine the minimum amount of gas 
detectable in the spectrum of a planet. 
Carbon wboxide was prepared by pyrolysis of 
diacetyltartaric anhydride as described in Part I. The 
gas was placed in a cell of 10-cm length having NaCl 
windows, with total thickiiess 4 mm, and the spec- 
trum was traced with a Beckman IR-4 spectrometer 
having an NaCl prism. 
Figure 1 shows three spectra: two different 
amouiiis of C:<02 and a blank run with the gas cell 
evacuated. Some small residual absorptions are seen 
in the spectrum of the gas cell alone; thece are attrib- 
uted to impurities in the NaCl windows, including 
absorbed water. The Beckman IR-4 spectrometer is 
a double-beam instrument and thus compensates for 
the strong absorptions of C 0 2  and H 2 0  in the air 
path in the optical path. From 15p-16.7 ,u (near the 
Img  wavelength limit 01 the instrument) the com- 
pensation is not complete; and this region, which 
does not contain G O 2  bands significant here, is not 
included in Figure 1. 
In Figure 1, spectrum (b) was obtained with 
a partial pressure of 5.5 mm Hg of C,O, in the IO-cm 
gas cell, or 0.72 mm-atm. The gas cell was connected 
wy. .. , the reservoir of liquid CxOa at -79" C; 5.5 mm 
Hg is the vapor pressure at this temperature (Hund- 
book of Chemistry and Physics). Spectrum (c) was 
obtained with the cell having been filled by flushing 
it with vapor of the boiling liquid CaO, at room 
temperature. 
The wavelength calibration of the spectrometer 
was checked by operating it in a single-beam mode 
so that the absorptions of the air path in the optical 
train would be recorded. The v:< band of COz at 
4.26 p (2349 cin-') was used for this purpose. 
Slight shifts in the scale on the recording paper were 
noted that correspond to rC35 cm-1 at 3500 cm-* 
and + l o  cm-' at 1000 cni-'. 
The positions of the fundamental infiared active 
bands with their permitted binary and ternary com- 
binations are indicated in the lower scale of Figure 1. 
These data were tuhcii from the computations of 
Dr. Fink (Part 111). 
The pyrolysis of diacetyltartaric anhydride yields 
acetic acid, carbon dioxide, and carbon monoxide 
as byproducts. To test for these contaminaiits in the 
spectrum of C:{O,, we made individual spectral trac- 
ings with various quantities of each cor:;aund using 
the sane spectrometer. In Figure 1 \vu have indi- 
cated the positions of the absorption bands due in 
part to possible conraminants. The coincidence l:f 
bands of Cor, CO, and CH:{COOH with those of 
C:r02 may be partially caused by the C-0 bonds 
common to all of these compounds. In no case is 
the contamination of the Cs02 bands in Figure 1 
expected to be more than 3-5 percent. 
The most suitable band system foi tests in plan- 
etary atmospheres would be that centered near 
4.35 p (2300 cm-') were it not for the very strong 
CO, band at the same wavelength, making it unsuit- 
able for tests in the atmospheres of Venus and Mars. 
The most suitable band for tests in planetary atmos- 
pheres appears to be v4 at 6.37 p (1570 cm-"). 
We estimate on the basis of curve (b)  that 0.1 
mm-atm of C,O, would still be detectable in the 
infrared spectrum of a planet. This band thus pro- 
vides an exceedingly sharp test for the presence of 
carbon suboxide in planetary atmospheres provided 
the observations are made at high altitude. 
The baild at 3.23 p (3100 cm-') designated 
v: + qi may also provide a sensitive test in a more 
accessible spectral region, but higher resolution is 
required because of the sharpness of the band. 
Acknowledgments. - We are grateful to the 
Department of Chemistry of the University of Ari- 
7.0118 for thc use of the spectrometrr. The program 
of infrared spectroscopy at the Llinar and Planetary 
Laboratoly is supported by PlASA Grant NsG 
161-61. 
Fig. I The infrared spectrum of CO:. 1.0-1\'-0 p recorded with a Beckman IK-4 spectrometer. (a)  blank with only windows of 
NaCi in gas ccll. (b )  0.71 nim-atm C,O, at pressure 5.5 mni Hg. (c)  93 nim-atm Ca0: at pressure 705 mm Hg. Frequency scale 
as calibrated by manufacturer. 
PART III: CLASSIFICATION OF C302 VIBRATIONAL BANDS 
by Uw. FINK 
Department of Physics. University of Arizona 
t is now well established (see the references) that I C,O, is a linear molecule belonging to the point 
c roup D,h. The seven fundamental frequencies are 
listed in Table 1 together with their symmetry 
species. Bands hclonging to the symmetry species 
Xil l  and Il,, are infrared-active (Herzberg 1962, p. 
253 ff). 
The frequency of the bending mode vi is still in 
some doubt. Older papers (Long et al. 1954, Alek- 
sandrov et al. 1964) use the frequency of 192 cm-I 
for vi reported by O'Loane (1953). More recent 
measurements (Miller and Fateley 1964), however, 
indicate that the above identification is erroneous. 
A lower value of 63 cm (Miller et al. 1955) or 
72 cm-l (Smith and Leroi 1966) has been reported 
for the gas and liquid phases, respectively. These 
measurements are substantiated by thermodynamic 
calculations by McDougall et al. (1965) (61.6 cni-') 
and measurements of the fine structure of the band 
at 3200 cm-* by Lafferty et al. (1964) (25-70cm-'). 
In order io assign possible transitions to the ob- 
served bands. all binary and ternary infrared-active 
bands were calculated from the fundamentals listed 
in Table 1. They are given with increasing wave- 
lengths in Table 2. The more recent value of 63 
cm-' for vi was preferred but calculations were made 
also with the older value of 190 cm-l. The latter 
numbers are put in brackets in the Tables. Since vg 
has such a low frequency, the state, v1 v2 v, v, v5 vG 
with I' = 0 and vT with V = 1, can have a popula- 
tion comparable to the ground state. Difference 
bands with vi can then be quite strong and are there- 
fore included in the Tables. 
In Table 4 is presented a comparison between 
206 U w e  F I N K  
the bands observed in the laboratory in the 1-2.5 p 
region and the ones listed in Tables 2 and 3. Of the 
possible binary combinations, only vI + v:r is within 
this wavelength region. It is clear that it must be 
identified with the strong band at 4430 crn-'. The 
weaker bands are probably due to ternary combina- 
tions. From the tiiblc it can be seen that a plausible 
identification can be made for every observed fea- 
ture. Errors in the fundamental frequencies as well 
as neglect of the anharmonicity constants and of 
Fermi resonance can easily account for the differ- 
ences between the observed and calculated fre- 
quencies. Their effects must be examined more 
thoroughly if a niore precise identification of the 
spectrum is desired. 
- n  v+ 4470 2.24 
y+ 3710 2.65 
14-3 
23-3 - n  3100 3.23 ,-i 
1 4-4 
34-5 11, 2850 3.51 
11. 2750 3.64 
24QO 4.17 
14-6 
2 1 4  ,. .b 
I +7 
24-6 
5+6 
2+7 
:-* 758 2263123901 1151) 2 137(20101 
I380 
1130 
8931 10201 
i42(4.18/ 
4.65 
4.66(4.981 
7.25 
8.85 
I I .2019.801 
2-7* 11, 7671640) . I3.04i I5.6i 
54-7 y+ 643i7701 15.55[13.0] 
5-778 V+" 51313901 19.5(25.6] 
"Difference bands with P: were included because of its low 
frequercy and the consequent population of that state. 
Numbers in brackets are calculated with the value of 
190 cni-' for Y:. 
~~ ~ _ _  
REFERENCES 
Aleksandrov, A. P., Tyulin. V. I., and Tatevskii, 
V. M. 1964, Optics atd Spectroscopy, 17, 19. 
Herzberg, G. 1962, ltifrared atid Ratiiaii Spectra of 
Polyaroinic Molrcdes (New York: D. van Nos- 
trand Co., Inc.). 
Lafferty, W. J., Maki, A. G., and Plyler, E. K. 1964. 
J .  Chetii. Pliys., 40, 224. 
Long, D. A., Murfin, F.S., and Williams, R. L. 1954, 
Proc. Roy. Snc. London, A223,25 1. 
McDougall, L. A., and Kilpatrick, 3. E. 1965, J .  
Cliein. Piiys., 42, 23 1 1. 
Miller, F. A., and Fateley, W. G. 1964, Spectrochitn. 
Acia 20, 253. 
_ .  
3 + 3 + 3  
1 + 1 + 3  
3+3+4 
1+1+4 
3+4+4 
1+2+3 
3+3+6 
1 + 3 + 5  
1+1+6 
4+4+4 
3+3+7 
3+3-778 
1+1+7 
3+4+6 
1+4+5 
I+1-7* 
2 + 2 + 3  
3+4+7 
3+4-77" 
4+4+6 
2 + 3 + 5  
1+2+6 
3 + 5 + 5  
3+6+6 
1+5+6 
2+2+4 
4+4+7 
I +1+7 
2+4+5 
1+2-7* 
3+6+7 
1 + 5 + ?  
1+2+4 
3+6-7* 
; : ; : ;78 
4+6+6 
3+7+7 
34-7-7* 
2+2+6 
4 + 6 + 7  
2+5+-6 
2+2+7 
5+5+6 
4+7+7 
6+6+6 
2+5+7 
5+5+7 
6+6+7 
7+7+7 
2+2-7* 
2+5-7* 
-~ - 
~~ ~ 
6810 
6670 
61 10 
5970 
5410 
5300 
5090 
5050 
4950 
4710 
4603[47301 
J6Q0 
447 7133 20 I 
4463145901 
4390 
4350 
4337142 101 
3920 
3903140201 
3777j2650) 
3690 
3680 
3550 
3430 
3370 
3330 
3230 
32031 3 3 301 
3093[3220] 
2980 
2967(28401 
2883[30lQl 
2843119701 
2757126301 
2730 
2717[2590! 
2670 
239 6126501 
2270 
2210 
7183(23 101 
1960 
17231 I SSOl 
1710 
I6961 19501 
1650 
1597(14701 
l473( I60Oj 
1347(12201 
I2231 13501 
1163[12901 
189[5701 
-~ 
1.47 
I .so 
1.64 
I .68 
I .85 
I .89 
I .96 
I .9X 
2.02 
2.12 
2.17[2.111 
2.17 
22312.301 
2.2412. IS1 
2.28 
2.30 
2.7 I 
2.72 
2.79 
2.92 
2.97 
3.00 
3.10 
3.12r3.001 
3.2jS. t I I 
3.36 
33713.521 
3.4713.321 
35213.371 
3.6313.801 
3.66- . 
3.68[3.S51 
3.75 
4.1713.771 
4.4 1 
4.52 
4.5SI4.33l 
5.10. . 
5.80[5.41 I 
5.65 
5.901s. I 31 
6.06 
~.26r6.80 
6.7916.25 
7.42[ 8.211 
8.1817.41 
53.91 17.5) 
8.6017.75 
"Dilkrence bands with 1': (see Table 2). 
Miller, F. A., Lemmon, D. €4.. and Witkowski, R. E. 
1965, Spectrocliiiti. Acta 21, 1709. 
OLoane, J. K. 1953, J .  Clietri. Pliys. 21,672. 
Smith, W. H., arid Leroi, G. E. 1966, J .  Clieni. Piiys. 
45, 1767. 
TdE S P E C T R U h f  O F  C A R B O N  s l J l 3 O X l D S  O N  V E N U S  207 


The infrared spectrum of carbon suboxide. Part 1 - Region 1-2.5 microns.  Part 2 - Region 2-15 microns.  Part 3 - Classification of carbon suboxide vibrational bands

The infrared spectrum of carbon suboxide. Part 1 - Region 1-2.5 microns. Part 2 - Region 2-15 microns. Part 3 - Classification of carbon suboxide vibrational bands

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