400
Francis P. Daly and Chris W. Brown could be obtained about the CTAB surfactant, which may play an important role in the adsorption and formation of the monolayer a t the interface. From this point of view, a succeeding study is in progress by using surface-active dyes which give rise to the resonance Raman effect for the exciting lights of Ar+ laser. The total reflection method described in this paper may be applied to studies of thin layers not only at liquid-liquid interfaces but also a t liquid-gas and liquid-solid interfaces.
References and Notes
iI
IlY
(1)A. G. Tweet, Rev. Sci. lnstrum., 34, 1412 (1963). (2)A. G. Tweet, G. L. Gaines. Jr.. and W. D. Bellamy, J. Chem. Phys., 40, 2596 (1964). (3) C. F. Hiskey and T. A. Downey, J. Phys. Chem., 58,835 (1954). (4) B. Kim, A. Kagayama, Y. Saito, K. Machida, and T. Uno, Bull. Chem. SOC.Jpn., 48, 1394 (1975). (5) H. H. Jaffe, S. J. Yeh, and R. W. Gardner, J. Mol. Spectrosc., 2, 120
Wavenumber
,
cm-l
Resonance Raman spectra of MO in the adsorbed monolayer obtained with four polarization geometries. Flgure 7.
(1956). (6) D. L. Beveridge and H. H. Jaff6, J. Am. Chem. Soc., 88, 1948 (1966). (7)N. J. Harrick, "Internal Reflection Spectroscopy", Interscience, New York, N.Y., 1967,Chapter II. (8) H. Hacker, Spectrochim. Acta, 21, 1969 (1965). (9) P R. Carey, H. Schneider, and H. J. Bernstein, Biochem. Blophys. Res. Commun., 47,588 (1972). (IO) K. Machida, E. Kim, Y. Saito, K. Igarashi, and f. Uno, Bull. Chem. SOC. Jpn., 47,78 (1974). (11) J. Behringer, Observed Resonance Raman Spectra", in "Raman Spectroscopy", H. A. Szymanski, Ed., Plenum Press, New York, N.Y.,
SIN value is now being made by means of the time averaging using a computer in real time. Unipoint multiple reflection techniques" may also compensate for weakness of scattered Raman radiation. It should be noted here that we measured the resonance Raman spectra of the MO dye and could discuss only about the orientation of these dye molecules. No information
1967,Chapter 6. (12) In the monolayer, the number of the MO molecules in a unit volume is as large as a factor of IO4 times that in the bulk aqueous solution.
(13)E. E. Wilson, Jr., J. C. Decius, and P. C. Cross, "Molecular Vibrations", McGraw-Hill, New York, N.Y., 1955,Section 3-6. (14)R. G. Snyder, J. Mol. Spectrosc., 37,353 (1971). (15)Reference 13,Appendix I. (16)The intensity of the background due to carbon tetrachloride depends upon the polarization geometry because of polarization characteristics of the Raman bands of carbon tetrachloride.
(17) N. J. Harlick, Appl. Opt., 5, 1236 (1966).
Raman Spectra of Rhombic Sulfur Dissolved in Secondary Amines Francis P. Daiy and Chris W. Brown* Department of Chemistry, University of Rhode Island, Kingston, Rhode Island 0288 1 (Received June 30, 1975)
Raman spectra of rhombic sulfur dissolved in di-n-butylamine, di-n-propylamine, and dimethylamine have been measured for the first time. Bands due to Sd2- and SS"- were observed in the spectra of the din-butylamine and di-n-propylamine solutions, whereas only bands due to Ssn- appeared in the spectrum of the dimethylamine solution. Comparison of the results on secondary amine solutions with our previous results on primary amines indicates that the ability of secondary amines to form small ionic sulfur species is less than that of primary amines.
The Raman spectra of rhombic sulfur dissolved in ethylenediamine, n-propylamine, and monomethylamine have been reported previously.lJ New bands observed in the 100-600-~m-~region were attributed to the open chain polysulfides SSn-, Sd2-, and S3-. In this note we report the The Journal of Physical Chemistry, Voi. 84 No. 5, 1976
Raman spectra of rhombic sulfur dissolved in the following secondary amines: di-n-butylamine, di-n-propylamine, din-propylamine, and dimethylamine. Raman spectra were measured using a Spex Industries Model 1401 double monochromator with photon counting
48 1
Raman Spectra of Rhombic Sulfur TABLE I: Vibrational Frequencies (cm-' ) and Relative Intensities of Bands Assigned to Open Chain Polysulfides in the Raman Spectra of Rhombic Sulfur Dissolved in Primary and Secondary Amines S, in EDA
S, in CH,NH,
S, in
CA"2
195 vw
193 vw
245 vw 297 w 396 vs 434 s 502 m 533 s
242 vw
S, in (C,H,),NH
S, in )2"
S, in (C3H7)2"
s,2-
397 vs 438 s 505 m 534 w
234 vw 250 w 285 w 396 vs 439 s 500 m
399 vs 437 s 502 m 535 s
227 w ( p = 0.81) 272 w ( p = 0.63) 402 vs ( p = 0.38)
400
S,n-
S,'- and S,n-S,2-
s,2s3-
I
500
S,ns,2-
282 w 398 vs 439 s 500 m
600 600
Assignment
(CH3
I
I
300
200
I
500
I
I
,
I
400
300
200
I
FREQUENCY, CM-l
Figure 2. Raman spectra of (a) di-n-propylamine and (b) -lo-' sulfur in di-n-propylamine.
FREQUENCY, CM-'
Figure 1. Raman spectra of (a)di-n-butylamine and (b) -lo-' fur in di-n-butylamine.
M
M SUI-
detection and a C.R.L. Model 52-A argon ion laser emitting at 4880 8, (G150 mW power a t the sample). All spectra were measured with a spectral slit width
