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Vibrational spectra (matrix and vapour phase) and molecular force field of OVCl3
0584-8539/82/09096545$03.00/0 @ 1982 Pergamon Press Ltd.
Spectrochimico Acta, Vol. 38A, No. 9, pp. %5-%9, 1982 Printed in Great Britain.
Vibrational spectra (matrix and vapour phase) and molecular force field of OVCL R. R. FILGUEIRA*, L. L. FOURNIER and E. L. VARE-ITI* Departamento de Fisica and Area de Quimica Inorganica, Facultad de Ciencias Exactas, Universidad National de La Plata, 1900 La Plata, Argentina (Received 19 December 1981) Abstract-The
i.r. spectra of matrix isolated and vapour phase OVC& were investigated. From these studies several vibrational isotopic splittings due to the natural abundance of 3sCI/37Clwere observed. Force constants were calculated using vibrational frequencies, isotopic shifts, Coriolis coupling
constants and mean amplitudes of vibration.
INTRODUCTION
The details of the instrument for low temperature studies
The molecular force field of OVC13 has been studied by several workers H-41. MUELLERet al. [I] calculated the force constants in symmetry coordinates with the approximate FADINI’S method [5,6], CLARK and RIPPON [2] used the vibrational wavenumbers and Coriolis coupling constants to estimate the E-species force constants, whereas HOVDAN et al; [3] calculated the vibrational isotopic splitting for the different 35C1/37C1isotopomers of OVCL using their own force field. Finally, KARAKIDAand KUCHITSU [4] obtained a set of force constants from the vibrational wavenumbers. All these studies were approximate because sufficient additional data were not available. As a part of a series of studies of the molecular force field of XYZ3 (C3”) compounds [7,8], the determination of a more accurate and reliable molecular force field for 0VC13 was undertaken. In this study, the i.r. spectrum of 0VC13 isolated in argon and krypton matrices was investigated in order to obtain the vibrational isotopic shifts. Besides, the i.r. spectrum in vapour-phase was partially measured. The vapour phase vibrational frequencies, isotopic shifts, Coriolis coupling constants [2] and mean amplitudes of vibration [4] were employed as input data for the force constant calculation.
are given elsewhere [8]. The vapour phase spectrum was
EXPERIMENTAL
0VC13 was obtained from a commercial source (purity over 99%) and degasified by means of several coolingvacuum-warming cycles prior to its use. The argon and krypton used in the low temperature (11-13 K) matrix experiments were nominally 99.997% and 99.99% pure, respectively. The sample/matrix mixtures, ranging from l/300 to l/1500, were prepared using standard manometric procedures and deposited in pulses onto a cooled CsI plate.
*Consejo National Tecnicas, Argentina.
de Investigaciones
Cientfficas y 965
measured at room temperature in a 10 cm glass cell with CsI windows. The spectra were recorded on a PerkinElmer 180 spectrophotometer with a resolution of OS1 cm-‘. Calibration was performed in the usual way 19,101. Figures 1 and 2 show some of the fundamentals of OVCIp as obtained from vapour phase and matrix isolation studies. Due to the existence of “Cl and “Cl isotopes in natural abundance, four different species are present. In the predicted isotopic splitting pattern, each of the three nondegenerate bands is composed of four lines. Each of the three degenerate bands is composed of six lines but for the v, band, A” lines of C, species superimpose on E lines of 12,. species and only four lines should be observed in the spectrum. More details on isotopic splitting patterns and intensities can be found in refs. [8] and [14].
RlNJLTs AND DJSCUSSION
It was possible to measure the vl(Al), v2(AI) and fundamental bands for gaseous OVClJ at room temperature. The expected PQR structure of the band contour was observed for I+ and v2, with a P-R separation of 15 r+ 1 cm-’ and 15 +2cm-‘, respectively. These values are in agreement with the calculated P-R separation of 14.4 cm-’ (see e.g. [123). As can be appreciated in Fig. 1, the low frequency side of the Q branch in the v1 band contour shows some perturbation, probably due to unresolved hot bands, whereas three Q branches due to the most abundant 3s’37C1 isotopomers (Table 1) appear in the u2 band contour. On the other hand, the band contour of the v4 fundamental does not show resolved features. The chlorine isotopic splitting (natural abundance) could be measured in the v2 and v4 bands for OVC13 isolated in Ar and Kr matrices (Fig. 2 and Table 1). No isotopic splitting was observed in the u, fundamental. The v2 isotopic shifts measured in the gas phase and in the matrices were coincident within the experimental error. General isotopic rules for heavy atom substitution Q(E)
.- ,
- -
.^__. _ _
1060
1040 1030
”
A
430
420
410 400 Wavenumber lcni’l
I
I
_.I--^
1035
1030
A
515
505 Wavenumber
510
500
Kr matrix
Icrri?
520
__.__
__.._
- -
- _
510
b
415
_ _. _. .
_
u
-.
7
*,
-
405
_
Ar matrix
Y,, Q and v,.
410
490
^
Ye, u2 and
500
in the region of the fundamentals
A
Fig. 2. Infrared spectrum of matrix isolated OVCIJ in the region of the fundamentals
1040
v4.
Fig. 1. Infrared spectrum of OVCI, in vapour phase, at room temperature,
1050
__
i
I
Vibrational spectra (matrix and vapour phase) Table 1. Observed wavenumbers Vapour phase Band v,(A,) vz(A,) v3Ud
V6(W
OVCI, 1042.8 * 0.W 411.3* 1.0t 2 0.5$ + 1.0t * 0.5$ 2 2.0$
OVWl
v2
V4
3
%7
and chlorine isotopic shifts, in cm-’
OV”C1 3
ov’~cl~“‘cl*
413.2kO.5
- 3.2 + 0.2
0V”Clf
ov”cl~‘cl~ - 6.3 t 0.2
ov~‘cl*“cl*
1037.1 * 0.5 413.2 2 0.5 510.0*0.5
- 9.6 + 0.3 - 5.8 2 0.2
1036.2 -c0.5 410.3 f 0.5 506.6 f 0.5
- 5.7 + 0.2
OV’JCl”C1 j
- 3.2 rt 0.2(A’) - 3.7 f 0.2(A’) 0.0 2 0.2(A”)
- 6.3 r 0.2(A’) - 1.8 r 0.2(A’) - 5.8 r 0.2(A”)
- 3.12 0.2(A’) - 3.7 f 0.2(A’) 0.0 2 0.2(A3
- 6.2? 0.2(A’) - 1.8 + 0.2(A’) - 5.7 2 0.2(N)
Kr matrix VI Y
V4
isotopic shifts are measured respect to OV”C1,. tThis work. *From Raman measurements [2]. *All
Table 2. Input data, uncertainties OVWl
and error vectors for the force constant calculation* OV”Cl35
3
Band
0bs.t
(r
E**
0bs.t
u
vt(AJ
1042.8 413.2 163.0$ 508.4 246.0$ 124.5$
10 4 3 5 3 3
0.8 0.3 -0.6 0.0 - 0.5 - 2.7
0.0 -9.6
0.3 0.3
0.10 -0.12
-5.7
0.2
0.05
v2b41)
I v,(E) v,(E) v6(‘9
ov~‘c12Wlg
v&4’) Y(A’) v&A’) (A”)
0.0 -3.2 - 3.7 0.0
OV35Cl37C12Q
0.3 0.2 8:;
0.03 -;g 0:09
Mean amplitudes
lov(298
K)
Iv&298 K) Io.a(298 K) L.c,(298 K)
e**
0.0 -6.3 - 1.8 -5.7
0.3 0.2 0.2 0.2
0.07 0.11 0.09 -0.04
Coriolis constants
Ohs!’
u
c**
0.041 0.048 0.086 0.112
0.006 0.003
0.004
oO:Z
-Ez?5 -0.004
{, 55 l6
0bs.S
Ca1c.t
0.55 - 0.75
0.70 0.65 - 0.60
*All wavenumbers and shifts are given in cm-‘, mean amplitudes in A and c’s are dimensionless. tThis work. SFrom Raman measurements [2]. QAll isotopic shifts are measured respect to 0V3’ClS. IlFrom ref. [4]. **e = x,. - x4,.
%8
R. R. FILCXJEIRA,L. L. FOURN~ER and E. L. VARET~
Table 3. Force constants of OVClr in symmetry coordinates*
F(l, 1) F(l,2) F&3) F(2,2) F(2,3) F(3,3) F(4,4) F(4,5) F(4,6) F(5,5) F(5,6) F(6,6)
OV-stretch VCl,-s-stretch VCl,-s-bend VCI,-a-stretch VCl-rock VCl+-bend
This work
Ref. [4]
7.94 + 0.14 1.06 f 0.53 0 3.08 f 0.13 0.00 + 0.08 0.63 -r-0.02 2.44” 0.04 0.12 f 0.08 0.24 rt_0.09 0.66 * 0.03 -0.11 -to.04 0.55 f 0.06
7.72 0.20 0.077 3.01 0 0.625 2.07 -0.13 0.16 0.78 -0.19 0.52
Stretching force constants in valence coordinates ovc19 &“c, &1
7.94 0.61 *f 0.14 0.30 0.21 2.65 2* 0.06 0.07
vcl4t
0.26 2.34
*Stretching force constants are given in mdyn A--‘, bending force constants in mdyn A and bending-stretching interaction force constants in mdyn. tFrom ref. [13].
[ 1l] were used for a check of the measured isotopic shifts. The following geometrical parameters for the molecule were used in the force constant calculation [4]: r(V0) = 1S70 A, r(VC1) = 2.142 A and XlVCl = 111.3”. Unscaled symmetry coordinates, analogous to those used by FILGUEIRA et al. [8] were employed. Table 2 shows all input data used in our calculation, in which an initial set of force constants [l] was refined using a least-squares refinement program. The data were sufficient to fix five force constants in the A, symmetry block (Fr3 was constrained to zero) and all the constants in the E block. The calculated force constants in symmetry coordinates are given in Table 3 along with those constants reported by KARAKIDA and KUCHITSU [4]. Some internal coordinate force constants are also given in this table together with the corresponding values for VCl, [13]. It is rather surprising the relatively large value obtained for fovlvc,.Despite the uncertainty in this value such a result should suggest a rather extensive electronic redistribution during the vibrations of these bonds as occurs, for example, in simpler molecules having adjacent single and multiple bonds, and central atoms belonging to the second period of the periodic table (ONHal, [15-181; NCHal, [19,20]; OCHal,, [21,22]; SCHalr or SeCHalz, [22]). Acknowledgements-We are particularly grateful to Professor Dr. ACHIMMILLER for his generous hospitality during the development of a part of this work at the University of Bielefeld, West Germany. R.R.F.
wishes to thank the Alexander von Humboldt Foundation, West Germany, for the award of a research fellowship. REFZRENCJB
[l] A. MILLER, B. KREBS,A. FADINI,0. GLEMSER, S. J. CYVIN, J. BRUNVOLL,B. N. CYVIN, I. ELVEBREDD, G. HAGEN and B. VIZI, 2. Nuturforsch. 23a, 1656 (1%8). [23 R. J. H. CLARK and D. M. RIPPON, Mol. Phys. 28, 305 (1974). [3] H. HOVDAN, S. J. CYVIN and W. BROCKNER, 2. Naturforsch. 29a, 706 (1974). [4] K. KARAKIDAand K. KUCHISTU,Inorg. Chim. Actn 13, 113 (1975). [5] A. FADINI, 2. Angew. Math. Mech. 44,506 (1%4). [6] W. SAWODNY,A. FADINI and K. BALLEIN, Spectrochim. Actu 21A, 995 (1965). [7] E. L. VARE~TI, R. R. FILGUEIRAand A. MILLER, Spectrochim. Acta 37A, 369 (1981) (FMnO,); A. MOLLER, R. R. FILGUEIRAand L. L. FOURNIER,to be published (SPCh). [8] R. R. FILCUEIRA, C. E. BLOM and A. MOLLER, Spectrochim. Acta 36A, 745 (1980). [93 L. R. BLAINE, E. K. PLYLERand W. S. BENEDICT,.I. Res. Nat. Bur. Std. A&. 223 (1%2). [lo] IUPAC Commision on Moiecular Structure and Spectroscopy, Table of Wavenumbers for the Calibration of Infrared Spectrometers. Butterworths, London (1961). ill] N. MOHANand A. MULLER, Spectrochim. Acta 33A, 799 (1977); N. MOHAN and A. MOLLER, .I. Chem. Phys. 67, 295 (1977). [12] W. A. SETH-PAUL, .I. Mol. Struct. 3,403 (1%9). [13] Y. MOR~NOand H. UEHARA,J. Chem. Phys. 45,4543 (1%6). 1141 S. T. KING, J. Chem. Phys. 49, 1321 (1968). [15] L. H. JONES, L. B. ASPREY and R. R. RYAN, .I. Chem. Phys. 47, 3371 (1967). [16] J. LAANE, L. H. JONES, R. R. RYAN and L. B. ASPREY,J. Mol. Spectrosc. 30,485 (1%9).
Vibrational spectra (matrix and vapour phase) [17] L. H. JONES, R. R. RYAN and L. B. ASPREY, J. Chem. Phys. 49,581 (1968). [18] G. CAZZOLI, R. CERVELLATI and A. M. MIRRI, J. Mol. Spectrosc. 56,422 (1975). [19] A. RUOFF, Spectrochim. Acta tiA, 545 (1970). [20] V. K. WANG and J. OVEREND, Spectrochim. Acta 29A, 1623 (1973).
969
I211 H. J. BECHERand A. ADRIAN, J. Mol. Struct. 7, 323 (1971). [221 A. HAAS, H. WILLNER, H. BORGER and G. PAWELKE, Spectrochim. Acta 33A, 937 (1977).
Spectrochimico Acta, Vol. 38A, No. 9, pp. %5-%9, 1982 Printed in Great Britain.
Vibrational spectra (matrix and vapour phase) and molecular force field of OVCL R. R. FILGUEIRA*, L. L. FOURNIER and E. L. VARE-ITI* Departamento de Fisica and Area de Quimica Inorganica, Facultad de Ciencias Exactas, Universidad National de La Plata, 1900 La Plata, Argentina (Received 19 December 1981) Abstract-The
i.r. spectra of matrix isolated and vapour phase OVC& were investigated. From these studies several vibrational isotopic splittings due to the natural abundance of 3sCI/37Clwere observed. Force constants were calculated using vibrational frequencies, isotopic shifts, Coriolis coupling
constants and mean amplitudes of vibration.
INTRODUCTION
The details of the instrument for low temperature studies
The molecular force field of OVC13 has been studied by several workers H-41. MUELLERet al. [I] calculated the force constants in symmetry coordinates with the approximate FADINI’S method [5,6], CLARK and RIPPON [2] used the vibrational wavenumbers and Coriolis coupling constants to estimate the E-species force constants, whereas HOVDAN et al; [3] calculated the vibrational isotopic splitting for the different 35C1/37C1isotopomers of OVCL using their own force field. Finally, KARAKIDAand KUCHITSU [4] obtained a set of force constants from the vibrational wavenumbers. All these studies were approximate because sufficient additional data were not available. As a part of a series of studies of the molecular force field of XYZ3 (C3”) compounds [7,8], the determination of a more accurate and reliable molecular force field for 0VC13 was undertaken. In this study, the i.r. spectrum of 0VC13 isolated in argon and krypton matrices was investigated in order to obtain the vibrational isotopic shifts. Besides, the i.r. spectrum in vapour-phase was partially measured. The vapour phase vibrational frequencies, isotopic shifts, Coriolis coupling constants [2] and mean amplitudes of vibration [4] were employed as input data for the force constant calculation.
are given elsewhere [8]. The vapour phase spectrum was
EXPERIMENTAL
0VC13 was obtained from a commercial source (purity over 99%) and degasified by means of several coolingvacuum-warming cycles prior to its use. The argon and krypton used in the low temperature (11-13 K) matrix experiments were nominally 99.997% and 99.99% pure, respectively. The sample/matrix mixtures, ranging from l/300 to l/1500, were prepared using standard manometric procedures and deposited in pulses onto a cooled CsI plate.
*Consejo National Tecnicas, Argentina.
de Investigaciones
Cientfficas y 965
measured at room temperature in a 10 cm glass cell with CsI windows. The spectra were recorded on a PerkinElmer 180 spectrophotometer with a resolution of OS1 cm-‘. Calibration was performed in the usual way 19,101. Figures 1 and 2 show some of the fundamentals of OVCIp as obtained from vapour phase and matrix isolation studies. Due to the existence of “Cl and “Cl isotopes in natural abundance, four different species are present. In the predicted isotopic splitting pattern, each of the three nondegenerate bands is composed of four lines. Each of the three degenerate bands is composed of six lines but for the v, band, A” lines of C, species superimpose on E lines of 12,. species and only four lines should be observed in the spectrum. More details on isotopic splitting patterns and intensities can be found in refs. [8] and [14].
RlNJLTs AND DJSCUSSION
It was possible to measure the vl(Al), v2(AI) and fundamental bands for gaseous OVClJ at room temperature. The expected PQR structure of the band contour was observed for I+ and v2, with a P-R separation of 15 r+ 1 cm-’ and 15 +2cm-‘, respectively. These values are in agreement with the calculated P-R separation of 14.4 cm-’ (see e.g. [123). As can be appreciated in Fig. 1, the low frequency side of the Q branch in the v1 band contour shows some perturbation, probably due to unresolved hot bands, whereas three Q branches due to the most abundant 3s’37C1 isotopomers (Table 1) appear in the u2 band contour. On the other hand, the band contour of the v4 fundamental does not show resolved features. The chlorine isotopic splitting (natural abundance) could be measured in the v2 and v4 bands for OVC13 isolated in Ar and Kr matrices (Fig. 2 and Table 1). No isotopic splitting was observed in the u, fundamental. The v2 isotopic shifts measured in the gas phase and in the matrices were coincident within the experimental error. General isotopic rules for heavy atom substitution Q(E)
.- ,
- -
.^__. _ _
1060
1040 1030
”
A
430
420
410 400 Wavenumber lcni’l
I
I
_.I--^
1035
1030
A
515
505 Wavenumber
510
500
Kr matrix
Icrri?
520
__.__
__.._
- -
- _
510
b
415
_ _. _. .
_
u
-.
7
*,
-
405
_
Ar matrix
Y,, Q and v,.
410
490
^
Ye, u2 and
500
in the region of the fundamentals
A
Fig. 2. Infrared spectrum of matrix isolated OVCIJ in the region of the fundamentals
1040
v4.
Fig. 1. Infrared spectrum of OVCI, in vapour phase, at room temperature,
1050
__
i
I
Vibrational spectra (matrix and vapour phase) Table 1. Observed wavenumbers Vapour phase Band v,(A,) vz(A,) v3Ud
V6(W
OVCI, 1042.8 * 0.W 411.3* 1.0t 2 0.5$ + 1.0t * 0.5$ 2 2.0$
OVWl
v2
V4
3
%7
and chlorine isotopic shifts, in cm-’
OV”C1 3
ov’~cl~“‘cl*
413.2kO.5
- 3.2 + 0.2
0V”Clf
ov”cl~‘cl~ - 6.3 t 0.2
ov~‘cl*“cl*
1037.1 * 0.5 413.2 2 0.5 510.0*0.5
- 9.6 + 0.3 - 5.8 2 0.2
1036.2 -c0.5 410.3 f 0.5 506.6 f 0.5
- 5.7 + 0.2
OV’JCl”C1 j
- 3.2 rt 0.2(A’) - 3.7 f 0.2(A’) 0.0 2 0.2(A”)
- 6.3 r 0.2(A’) - 1.8 r 0.2(A’) - 5.8 r 0.2(A”)
- 3.12 0.2(A’) - 3.7 f 0.2(A’) 0.0 2 0.2(A3
- 6.2? 0.2(A’) - 1.8 + 0.2(A’) - 5.7 2 0.2(N)
Kr matrix VI Y
V4
isotopic shifts are measured respect to OV”C1,. tThis work. *From Raman measurements [2]. *All
Table 2. Input data, uncertainties OVWl
and error vectors for the force constant calculation* OV”Cl35
3
Band
0bs.t
(r
E**
0bs.t
u
vt(AJ
1042.8 413.2 163.0$ 508.4 246.0$ 124.5$
10 4 3 5 3 3
0.8 0.3 -0.6 0.0 - 0.5 - 2.7
0.0 -9.6
0.3 0.3
0.10 -0.12
-5.7
0.2
0.05
v2b41)
I v,(E) v,(E) v6(‘9
ov~‘c12Wlg
v&4’) Y(A’) v&A’) (A”)
0.0 -3.2 - 3.7 0.0
OV35Cl37C12Q
0.3 0.2 8:;
0.03 -;g 0:09
Mean amplitudes
lov(298
K)
Iv&298 K) Io.a(298 K) L.c,(298 K)
e**
0.0 -6.3 - 1.8 -5.7
0.3 0.2 0.2 0.2
0.07 0.11 0.09 -0.04
Coriolis constants
Ohs!’
u
c**
0.041 0.048 0.086 0.112
0.006 0.003
0.004
oO:Z
-Ez?5 -0.004
{, 55 l6
0bs.S
Ca1c.t
0.55 - 0.75
0.70 0.65 - 0.60
*All wavenumbers and shifts are given in cm-‘, mean amplitudes in A and c’s are dimensionless. tThis work. SFrom Raman measurements [2]. QAll isotopic shifts are measured respect to 0V3’ClS. IlFrom ref. [4]. **e = x,. - x4,.
%8
R. R. FILCXJEIRA,L. L. FOURN~ER and E. L. VARET~
Table 3. Force constants of OVClr in symmetry coordinates*
F(l, 1) F(l,2) F&3) F(2,2) F(2,3) F(3,3) F(4,4) F(4,5) F(4,6) F(5,5) F(5,6) F(6,6)
OV-stretch VCl,-s-stretch VCl,-s-bend VCI,-a-stretch VCl-rock VCl+-bend
This work
Ref. [4]
7.94 + 0.14 1.06 f 0.53 0 3.08 f 0.13 0.00 + 0.08 0.63 -r-0.02 2.44” 0.04 0.12 f 0.08 0.24 rt_0.09 0.66 * 0.03 -0.11 -to.04 0.55 f 0.06
7.72 0.20 0.077 3.01 0 0.625 2.07 -0.13 0.16 0.78 -0.19 0.52
Stretching force constants in valence coordinates ovc19 &“c, &1
7.94 0.61 *f 0.14 0.30 0.21 2.65 2* 0.06 0.07
vcl4t
0.26 2.34
*Stretching force constants are given in mdyn A--‘, bending force constants in mdyn A and bending-stretching interaction force constants in mdyn. tFrom ref. [13].
[ 1l] were used for a check of the measured isotopic shifts. The following geometrical parameters for the molecule were used in the force constant calculation [4]: r(V0) = 1S70 A, r(VC1) = 2.142 A and XlVCl = 111.3”. Unscaled symmetry coordinates, analogous to those used by FILGUEIRA et al. [8] were employed. Table 2 shows all input data used in our calculation, in which an initial set of force constants [l] was refined using a least-squares refinement program. The data were sufficient to fix five force constants in the A, symmetry block (Fr3 was constrained to zero) and all the constants in the E block. The calculated force constants in symmetry coordinates are given in Table 3 along with those constants reported by KARAKIDA and KUCHITSU [4]. Some internal coordinate force constants are also given in this table together with the corresponding values for VCl, [13]. It is rather surprising the relatively large value obtained for fovlvc,.Despite the uncertainty in this value such a result should suggest a rather extensive electronic redistribution during the vibrations of these bonds as occurs, for example, in simpler molecules having adjacent single and multiple bonds, and central atoms belonging to the second period of the periodic table (ONHal, [15-181; NCHal, [19,20]; OCHal,, [21,22]; SCHalr or SeCHalz, [22]). Acknowledgements-We are particularly grateful to Professor Dr. ACHIMMILLER for his generous hospitality during the development of a part of this work at the University of Bielefeld, West Germany. R.R.F.
wishes to thank the Alexander von Humboldt Foundation, West Germany, for the award of a research fellowship. REFZRENCJB
[l] A. MILLER, B. KREBS,A. FADINI,0. GLEMSER, S. J. CYVIN, J. BRUNVOLL,B. N. CYVIN, I. ELVEBREDD, G. HAGEN and B. VIZI, 2. Nuturforsch. 23a, 1656 (1%8). [23 R. J. H. CLARK and D. M. RIPPON, Mol. Phys. 28, 305 (1974). [3] H. HOVDAN, S. J. CYVIN and W. BROCKNER, 2. Naturforsch. 29a, 706 (1974). [4] K. KARAKIDAand K. KUCHISTU,Inorg. Chim. Actn 13, 113 (1975). [5] A. FADINI, 2. Angew. Math. Mech. 44,506 (1%4). [6] W. SAWODNY,A. FADINI and K. BALLEIN, Spectrochim. Actu 21A, 995 (1965). [7] E. L. VARE~TI, R. R. FILGUEIRAand A. MILLER, Spectrochim. Acta 37A, 369 (1981) (FMnO,); A. MOLLER, R. R. FILGUEIRAand L. L. FOURNIER,to be published (SPCh). [8] R. R. FILCUEIRA, C. E. BLOM and A. MOLLER, Spectrochim. Acta 36A, 745 (1980). [93 L. R. BLAINE, E. K. PLYLERand W. S. BENEDICT,.I. Res. Nat. Bur. Std. A&. 223 (1%2). [lo] IUPAC Commision on Moiecular Structure and Spectroscopy, Table of Wavenumbers for the Calibration of Infrared Spectrometers. Butterworths, London (1961). ill] N. MOHANand A. MULLER, Spectrochim. Acta 33A, 799 (1977); N. MOHAN and A. MOLLER, .I. Chem. Phys. 67, 295 (1977). [12] W. A. SETH-PAUL, .I. Mol. Struct. 3,403 (1%9). [13] Y. MOR~NOand H. UEHARA,J. Chem. Phys. 45,4543 (1%6). 1141 S. T. KING, J. Chem. Phys. 49, 1321 (1968). [15] L. H. JONES, L. B. ASPREY and R. R. RYAN, .I. Chem. Phys. 47, 3371 (1967). [16] J. LAANE, L. H. JONES, R. R. RYAN and L. B. ASPREY,J. Mol. Spectrosc. 30,485 (1%9).
Vibrational spectra (matrix and vapour phase) [17] L. H. JONES, R. R. RYAN and L. B. ASPREY, J. Chem. Phys. 49,581 (1968). [18] G. CAZZOLI, R. CERVELLATI and A. M. MIRRI, J. Mol. Spectrosc. 56,422 (1975). [19] A. RUOFF, Spectrochim. Acta tiA, 545 (1970). [20] V. K. WANG and J. OVEREND, Spectrochim. Acta 29A, 1623 (1973).
969
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