HIGH RESOLUTION RAMAN SPECTROSCOPY OF GASES: XIV. ROTATIONAL SPECTRA OF C2H6, C2D6, C2H3D3 AND STRUCTURE OF THE ETHANE MOLECULE

1962 ◽  
Vol 40 (3) ◽  
pp. 358-366 ◽  
Author(s):  
B. P. Stoicheff

An analysis of the rotational Raman spectra of three isotopic species of ethane has given the following values for the rotational constants:[Formula: see text]From these values alone it is found that r0(C—C) = 1.5376 ± 0.003 Å, and when these are combined with, already available values of Ia (the moment of inertia about the symmetric top axis), the CH3 parameters are determined to be r0(C—H) = 1.106 ± 0.006 Å and [Formula: see text].

1957 ◽  
Vol 35 (4) ◽  
pp. 373-382 ◽  
Author(s):  
J. H. Callomon ◽  
B. P. Stoicheff

The pure rotational Raman spectra of acetylene (C2H2), diacetylene (C4H2 and C4D2), and dimethylacetylene (C4H6) have been photographed with a 21-ft. grating spectrograph. The rotational constants were found to be B0(C2H2) = 1.1769 cm−1, B0(C4H2) = 0.14689 cm−1, B0(C4D2) = 0.12767 cm−1, and B0(C4H6) = 0.1122 cm−1. An analysis shows that r0(C—H) in diacetylene is shorter than in acetylene and cyanoacetylene; in dimethylacetylene at least one of the carbon–carbon bonds is longer than in the closely related molecule methylacetylene.


1954 ◽  
Vol 32 (5) ◽  
pp. 339-346 ◽  
Author(s):  
B. P. Stoicheff

The pure rotational Raman spectra of benzene and benzene–d6 at a pressure of [Formula: see text] atm. were photographed in the second order of a 21 ft. grating. Both spectra were resolved and analyzed, yielding for the rotational constants the values B0(C6H6) = 0.18960 ± 0.00005 cm.−1, B0(C6D6) = 0.15681 ± 0.00008 cm.−1and, therefore, for the moments of inertia about an axis perpendicular to the figure axis[Formula: see text]If it is assumed that the benzene molecule has the planar hexagonal structure, the moments of inertia just given yield for the internuclear distances in benzene the values[Formula: see text]


1964 ◽  
Vol 42 (11) ◽  
pp. 2259-2263 ◽  
Author(s):  
W. Jeremy Jones ◽  
B. P. Stoicheff

A high-resolution study of the rotational Raman spectra of cyclopropane and cyclopropane-d6 has yielded the values 0.66962 ± 0.00020 cm−1 and 0.46079 ± 0.00015 cm−1 for their ground-state rotational constants. From these values the C–C internuclear distance is determined to be 1.514 ± 0.002 Å.


1955 ◽  
Vol 33 (12) ◽  
pp. 811-818 ◽  
Author(s):  
B. P. Stoicheff

The pure rotational Raman spectra of allene, allene-d4 and allene-1,1-d2 were photographed in the second order of a 21 ft. grating. Two plates of each spectrum were analyzed yielding the following values for the rotational constants:[Formula: see text]These constants lead to the value r0(C=C) = 1.3088 ± 0.001 Å. Also if a value of r0(C—H) = 1.07 ± 0.01 Å is assumed, then [Formula: see text]. It is noted that the length of the carbon–carbon double bond in allene is significantly shorter than that in ethylene.


1956 ◽  
Vol 34 (10) ◽  
pp. 1016-1021 ◽  
Author(s):  
J. E. Lancaster ◽  
B. P. Stoicheff

The pure rotational Raman spectra of s-triazine (C3H3N3) and s-triazine-d3 (C3D3N3) vapor were photographed in the second order of a 21-ft. grating spectrograph. The rotational constants were found to be B0(C3D3N3) = 0.21460 ± 0.00008 cm−1 and B0(C3D3N3) = 0.19358 ± 0.00015 cm−1. These values, together with the assumption that the molecule is planar and has a CH bond length of 1.084 Å, give the following values for the structural parameters: r0(CN) = 1.338 ± 0.001 Å, [Formula: see text]NCN = 127°, and [Formula: see text]CNC = 113°.


1954 ◽  
Vol 32 (5) ◽  
pp. 330-338 ◽  
Author(s):  
B. P. Stoicheff

An apparatus for obtaining intense Raman spectra of gases excited by the Hg 4358 line is described. It consists of a mirror-type Raman tube irradiated by two high-current mercury lamps, completely enclosed in a reflector of magnesium oxide. The lamps are externally water-cooled along their entire length and emit sharp lines of high intensity.Rotational Raman spectra of gases at a pressure of 1 atm. have been photographed in the second order of a 21 ft. grating in exposure times of 6 to 24 hr. The Raman lines are sharp and a resolving power of about 100,000 has been achieved. It will be possible to resolve the rotational Raman spectra, and hence to evaluate the rotational constants of molecules having moments of inertia of up to 300 × 10−10 gm. cm.2 Such investigations will be especially useful for non-polar molecules.


1960 ◽  
Vol 38 (11) ◽  
pp. 1516-1525 ◽  
Author(s):  
K. Suryanarayana Rao ◽  
B. P. Stoicheff ◽  
R. Turner

The pure rotational spectra of gaseous Zn(CH3)2, Cd(CH3)2, Hg(CH3)2, and of the fully deuterated molecules have been photographed with a 21-ft grating. The spectra are typical of symmetric top molecules and consist of many evenly spaced rotational lines having a separation of about 0.45 cm−1. An analysis of the spectra yielded the rotational constants (in cm−1)[Formula: see text]From these constants the following metal—carbon bond lengths were determined: Zn—C = 1.929 Å, Cd—C = 2.112 Å, and Hg—C = 2.094 Å. Relations for the C—H bond lengths and HCH angles were also obtained.


1962 ◽  
Vol 40 (6) ◽  
pp. 725-731 ◽  
Author(s):  
R. C. Lord ◽  
B. P. Stoicheff

An investigation of the rotational Raman spectra of normal and fully deuterated cyclobutane (C4H8 and C4D8) has given values of the rotational constants for these molecules. From these results it was found that the C—C bond length is 1.558 ± 0.003 Å, irrespective of whether cyclobutane belongs to the molecular point group D4h (planar C4 ring) or D2d (puckered C4 ring).


1959 ◽  
Vol 37 (6) ◽  
pp. 703-721 ◽  
Author(s):  
J. M. Dowling ◽  
B. P. Stoicheff

The pure rotational Raman spectra of C2H4 and C2D4 were photographed in the second order of a 21-ft grating. The resolution achieved was such that several lines due to single transitions were observed (and identified) in the spectra of both molecules. An analysis of these lines based on the non-rigid asymmetric top yielded the following rotational constants for the ground states:[Formula: see text]The structural parameters obtained from these constants are r0(C=C) = 1.339 ± 0.002 Å, r0(C—H) = 1.086 ± 0.003 Å, and [Formula: see text]. These values are in agreement with the recent preliminary results of the electron diffraction data. There is also agreement between the above values and those obtained from a recent study of the rotation–vibration spectra of C2H4 and C2D4, although the agreement between the ground state rotational constants is not as satisfactory.


1954 ◽  
Vol 32 (10) ◽  
pp. 630-634 ◽  
Author(s):  
B. P. Stoicheff

The pure rotational spectrum and the Q branch of the 1–0 band of N2 were photographed in the second order of a 21 ft. grating. An analysis of the rotational spectrum yields the rotational constants[Formula: see text]The value of B0 together with the Bν values obtained from the electronic bands of N2 gives[Formula: see text]Revised values of the vibrational constants have also been calculated using the results of the present work and the published data on the electronic spectra.


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