High resolution rotation–vibration Raman spectra of benzene. III. The spectrum of C6D6

1979 ◽  
Vol 57 (5) ◽  
pp. 767-774 ◽  
Author(s):  
A. B. Hollinger ◽  
H. L. Welsh ◽  
K. S. Jammu
Keyword(s):  
Raman Spectrum ◽  
High Resolution ◽  
Least Squares ◽  
Raman Spectra ◽  
Multiple Reflection ◽  
Slit Width ◽  
Molecular Constants ◽  
Least Squares Fit

The Raman spectrum of benzene-d6 vapour was excited in a multiple reflection cell by an Ar+ laser and was photographed with a spectral slit width of ~0.15 cm−1. Extensive structure (164 maxima) was observed for the ν2 (C—C stretching) fundamental but only the S branch (39 maxima) of the ν1 (C—D stretching) band was well-resolved. These totally symmetric bands were analysed and molecular constants determined from a least-squares fit. Three doubly degenerate bands were observed; ν15 and ν16 were unresolved, and in ν17 only 19 lines could be measured. Consequently, no detailed analyses were possible but the values of some molecular constants were estimated.

High resolution rotation–vibration Raman spectra of benzene. I. The totally symmetric bands of C6H6

1978 ◽  
Vol 56 (7) ◽  
pp. 974-982 ◽  
Author(s):  
A. B. Hollinger ◽  
H. L. Welsh
Keyword(s):  
Raman Spectrum ◽  
High Resolution ◽  
Least Squares ◽  
Raman Spectra ◽  
Multiple Reflection ◽  
Slit Width ◽  
Linear Least Squares ◽  
Raman Cell ◽  
Least Squares Minimization

The Raman spectrum of benzene vapour was excited in a multiple reflection Raman cell by an Ar+ laser and was photographed with a spectral slit width of ~0.17 cm−1. All seven Raman-active fundamentals were observed. Analyses of the totally symmetric ν1 and ν2 bands are given in this article. About 150 maxima were observed for ν2 (C—C stretching) and ~100 for ν1 (C—H stretching); the latter was to some extent obscured by the ν15 band. These partially resolved rotational structures were analyzed by setting up suitable schemes of approximate assignments for the maxima and calculating the band constants by a linear least-squares minimization.

High resolution rotation–vibration Raman spectra of benzene. II. The doubly degenerate bands of C6H6

1978 ◽  
Vol 56 (11) ◽  
pp. 1513-1525 ◽  
Author(s):  
A. B. Hollinger ◽  
H. L. Welsh
Keyword(s):  
Raman Spectrum ◽  
High Resolution ◽  
Computer Program ◽  
Raman Spectra ◽  
Multiple Reflection ◽  
Slit Width ◽  
Molecular Constants ◽  
Raman Cell

The Raman spectrum of benzene vapour was excited in a multiple reflection Raman cell by an Ar+ laser and was photographed with a spectral slit width of ~ 0.15 cm−1. The results for the five doubly degenerate Raman-active fundamentals are given in this communication. More than 150 maxima were resolved in the ν17 band and the spectrum was analyzed with a computer program to give ν17 = 1177.776(10) cm−1, B1 – B0 = 1.00(4) × 10−4, C1 – C0 = −0.50(2) × 10−4 cm−1, and ζ17 = 0.010(1). About 60 maxima were recorded in the ν18 band; molecular constants were determined but with less precision than for ν17. The ν15 band (partially overlapped by ν1) and the (ν16, ν2 + ν18) Fermi diad showed resolved structure but no detailed analyses were possible. The ν11 band showed no resolved structure.

High resolution rotation–vibration Raman spectra of acetylene. I. The spectrum of C2H2

1980 ◽  
Vol 58 (4) ◽  
pp. 534-543 ◽  
Author(s):  
E. Kostyk ◽  
H. L. Welsh
Keyword(s):  
Raman Spectrum ◽  
High Resolution ◽  
Raman Spectra ◽  
Gas Pressure ◽  
Multiple Reflection ◽  
Slit Width ◽  
Lower State ◽  
Vibrational States ◽  
Band Origin ◽  
Raman Cell

The Raman spectrum of gaseous acetylene was excited in a multiple-reflection Raman cell by a single-moded Ar+ laser and recorded photographically; the gas pressure was 380 Torr and the spectral slit-width ~0.1 cm−1. The three Raman-active fundamentals ν1, ν2, and ν41 of C2H2 were analyzed to give the band origin, ν0, and the upper state constants, B1 and D1; accurate infrared values of the lower state constants, B0 and D0, were assumed in the analysis. The values of the constants for the ν2 band illustrate the accuracy obtained: ν0 = 1974.317(2), B1 = 1.170419(14), D1 = 1.579(18) × 10−6 cm−1. Five difference bands originating in transitions from the low-lying ν4 = 1 and ν5 = 1 vibrational states were also measured and analyzed.

High-resolution laser-excitation spectrum of the A2Π ← X2Σ system of TiN: rotational analysis of the 0–0, 1–1, and 2–2 bands

1985 ◽  
Vol 63 (7) ◽  
pp. 997-1004 ◽  
Author(s):  
K. Brabaharan ◽  
J. A. Coxon ◽  
A. Brian Yamashita
Keyword(s):  
High Resolution ◽  
Least Squares ◽  
Excitation Spectrum ◽  
Laser Excitation ◽  
Rotational Analysis ◽  
Molecular Constants ◽  
Individual Bands ◽  
Measured Line ◽  
Line Positions ◽  
Π State

The 0–0, 1–1, and 2–2 bands of the A2Π ← X2Σ system of TiN have been recorded using the technique of laser-excitation spectroscopy. Molecular constants have been obtained from direct least squares fits of the measured line positions of individual bands. The fitted constants confirm and extend previous determinations; for the A2Π state, some of the constants show unusually large variations with ν, in accord with the already known perturbation of this state in the ν = 0 level.

High-Resolution Infrared Spectrum of Diazirine, H2CN2. Rovibrational Analysis of the Methylene Deformation Band

1988 ◽  
Vol 43 (4) ◽  
pp. 331-337 ◽  
Author(s):  
A. Gambi ◽  
A. Baldacci ◽  
S. Giorgianni
Keyword(s):  
Fourier Transform ◽  
High Resolution ◽  
Infrared Spectrum ◽  
Least Squares ◽  
Deformation Band ◽  
Fourier Transform Spectrometer ◽  
Centrifugal Distortion ◽  
Molecular Constants ◽  
Centrifugal Distortion Constants

Abstract The infrared spectrum of diazirine has been recorded at Doppler resolution with a high informa­tion Fourier transform spectrometer. The ν3 fundamental has been reinvestigated and the overall assignment of the rovibrational transitions has been carried out. From the least-squares analysis a more accurate set of molecular constants including the sextic centrifugal distortion constants has been determined for the level υ3 = 1 and will be reported here. The higher resolution achieved here allowed the assignment of weaker lines and many Q branch transitions. Moreover many blended lines have now been resolved and could be properly assigned.

Analysis of the high resolution spectrum of the ν2 and ν5 absorption bands of methyl chloride

1984 ◽  
Vol 62 (3) ◽  
pp. 247-253 ◽  
Author(s):  
M. Morillon-Chapey ◽  
G. Guelachvili ◽  
Per Jensen
Keyword(s):  
Standard Deviation ◽  
High Resolution ◽  
Infrared Spectrum ◽  
Least Squares ◽  
Methyl Chloride ◽  
High Resolution Spectrum ◽  
Vibrational States ◽  
Absorption Bands ◽  
Least Squares Fit

The infrared spectrum of methyl chloride CH3Cl between 1280 and 1650 cm−1 has been recorded at high resolution (0.005 cm−1). The Coriolis interactions between ν2(A1) and ν5(E) and between 2ν3(A1) and ν5 have been investigated through a least squares fit to the transitions observed for CH335Cl. Ten parameters for the three upper vibrational states and three interaction constants have been determined, reproducing the 1200 observed wavenumbers with a standard deviation of 0.002 cm−1. An accidental resonance of the type l(ΔK = 2, Δl = −1) between ν2 and ν5 was found to be present in the spectrum.

scholarly journals The Wilson-Bappu Effect for MG II K-Line Emission Widths

1985 ◽  
Vol 111 ◽  
pp. 381-383
Author(s):  
M. Parthasarathy
Keyword(s):  
High Resolution ◽  
Least Squares ◽  
Linear Correlation ◽  
Line Emission ◽  
Absolute Magnitude ◽  
Late Type ◽  
Least Squares Fit ◽  
Image Position

The existence of a tight linear correlation between the stellar absolute magnitude Mv and the Mg II k-line emission width log WMg II k (kms−1) is confirmed using IUE high-resolution (0.2A) data for 100 late-type stars. A least-squares fit to the data gives the relation:

Vibrational spectra and a force field for H2S3 and H2S4

1969 ◽  
Vol 47 (10) ◽  
pp. 1633-1637 ◽  
Author(s):  
H. Wieser ◽  
P. J. Krueger ◽  
E. Muller ◽  
J. B. Hyne
Keyword(s):  
Force Field ◽  
Least Squares ◽  
Concentration Dependence ◽  
Raman Spectra ◽  
Vibrational Spectra ◽  
Average Error ◽  
Infrared And Raman Spectra ◽  
Valence Force Field ◽  
Least Squares Fit ◽  
Complete Assignment

The infrared and Raman spectra of H2S3 and H2S4 in CCl4 and CS2 solutions are reported and a complete assignment is presented. On the basis of the spectra and their temperature and concentration dependence, H2S3 is considered to be in the GG and H2S4 in the GG′G conformation. A valence force field is derived which provides a least-squares fit between observed and calculated frequencies for both molecules simultaneously, with an average error of 1.5 cm−1 (or 0.4%) over all frequencies.

Constantes moléculaires de de NH2 : observation et estimation de la vibration ν3

1982 ◽  
Vol 60 (1) ◽  
pp. 49-55 ◽  
Author(s):  
M. Vervloet ◽  
M. F. Merienne-Lafore
Keyword(s):  
High Resolution ◽  
Emission Spectrum ◽  
Least Squares ◽  
Fluorescence Spectra ◽  
Fermi Resonance ◽  
Rotational Analysis ◽  
Least Squares Fit ◽  
Coriolis Perturbation ◽  
Effective Constants

From the high resolution photographic emission spectrum, a rotational analysis of the [Formula: see text] state of NH2 has been carried out. This analysis was aided by laser excited fluorescence spectra which exhibit some extra lines attributed to a Coriolis perturbation between the rotational levels of (100) and (001), [Formula: see text]. A Fermi resonance has also been observed between (100) and (020), [Formula: see text]. By deleting the perturbed rotational levels from the least squares fit, it has been possible to calculate some effective constants for the [Formula: see text] level with the origin at 3219.36 cm−1. In addition an estimated value of 3280 cm−1 is proposed for the frequency of ν3.

High resolution rotation–vibration Raman spectra of acetylene. II. The spectra of C2D2 and C2HD

1980 ◽  
Vol 58 (6) ◽  
pp. 912-920 ◽  
Author(s):  
E. Kostyk ◽  
H. L. Welsh
Keyword(s):  
High Resolution ◽  
Raman Spectra ◽  
Ground State ◽  
Multiple Reflection ◽  
Acetylene Molecule ◽  
Band Origin ◽  
Infrared Studies ◽  
Internuclear Distances ◽  
Raman Cell ◽  
Gas Pressures

The Raman spectra of gaseous C2D2 and C2HD were excited in a multiple-reflection Raman cell by a single-moded Ar+ laser and recorded photographically; the gas pressures were in the range, 130–200 Torr, and the spectral slit width was ~ 0.1 cm−1. The ν1, ν2, and ν41 bands of C2D2 and the ν1 and ν2 bands of C2HD were recorded. These were analyzed to give the band origin, ν0, and the upper state constants, B1 and D1; accurate infrared values of the ground state constants, B0 and D0, were assumed in the analyses. Values of the rotation–vibration interaction constants, αi, assembled from Raman and infrared studies of C2H2, C2D2, and C2HD, were used to calculate the equilibrium internuclear distances for the acetylene molecule: re(C—H) = 1.06250 ± 0.00010 and re(C≡C) = 1.20241 ± 0.00009 Å.

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