scholarly journals J-Dependence of T2-Parameters for Rotational Transitions of SO2 and CH3OH in K-Band

1985 ◽  
Vol 40 (7) ◽  
pp. 683-685 ◽  
Author(s):  
S. C. Mehrotra ◽  
H. Dreizler ◽  
H. Mäder
Keyword(s):  
Fourier Transform ◽  
Quantum Number ◽  
Ground State ◽  
Significant Variation ◽  
Vibrational State ◽  
Rotational Quantum Number ◽  
Fourier Transform Spectrometer ◽  
Ground Vibrational State ◽  
Rotational Transitions ◽  
Upper Level

With the help of a microwave Fourier transform spectrometer in the range from 18 GHz to 26 GHz, the coefficients ß for the linear pressure depedence of collisional dephasing rates 1/T2 have been determined by the transient emission technique for fourteen pure rotational transitions of SO2 with 5 ≦ J' ≦ 66 in the ground vibrational state, twelve transitions with 8 ≦ J' ≦ 62 in the first excited bending vibrational state, and twelve transitions of methanol with 2 ≦ J' ≦ 11, where J' is the rotational quantum number of the upper level of a transition. The T2-parameter ß for the transition J(K-, K+) - 49(4, 46 ) - 48(5, 43) of SO2 in the ground state shows an anomalous behaviour, whereas the values for all other transitions show a J-dependence in accordance with previous results. No significant variation of T2-parameters with J has been found for the rotational transitions of CH3OH.

A Contribution to the Investigation of T2-Relaxation: Rotational Transitions of OCS and SO2

1984 ◽  
Vol 39 (7) ◽  
pp. 633-636 ◽  
Author(s):  
S. C. Mehrotra ◽  
G. Bestmann ◽  
H. Dreizler ◽  
H. Mäder
Keyword(s):  
Fourier Transform ◽  
Quantum Number ◽  
Pressure Dependence ◽  
Ground State ◽  
Vibrational State ◽  
Room Temperature ◽  
Rotational Quantum Number ◽  
Lower State ◽  
T2 Relaxation ◽  
Microwave Spectrometer

With use of a Fourier transform microwave spectrometer in the range of 4 GHz to 18 GHz, the pressure dependence of collisional coherence dephasing times T2 at room temperature has been determined for (a) the transition J = 0 → J =1 of OCS, 18OCS, and OC34S, (b) nine transitions of SO2 in ground state having 13 ≦ J ≦ 59, and (c) eight transitions of SO2 having 12 ≦ 7 ≦ 55 in the first excited bending vibrational state, where J is the rotational quantum number of the lower state.

Millimeter Wave Rotational Transitions of 16O12C32S and 16O13C32S

1974 ◽  
Vol 29 (8) ◽  
pp. 1213-1215 ◽  
Author(s):  
N. W. Larsen ◽  
B. P. Winnewisser
Keyword(s):  
Excited States ◽  
Millimeter Wave ◽  
Vibrational Spectra ◽  
Vibrational State ◽  
Vibrational States ◽  
Ground Vibrational State ◽  
Wave Region ◽  
Rotational Transitions ◽  
Good Agreement

Rotational transitions of 16012C32S and 16013C32S in the ground vibrational state and of 16012C32S in several excited states have been accurately measured in the millimeter wave region for a minimum of four different J values. The analysis of the measured frequencies leads to rotational constants for the following vibrational states: 0 00 0 of 16O13C32S and 0 00 0, 0 1 1c 0, 0 1 1d 0, 0 20 0, 0 22c 0, 0 22d 0, 0 00 1 of 16O12C32S. Since the two components of the 0 22 0 transitions were resolved, an analysis of the l-type resonance was carried out and the interval 0 22 0 - 0 20 0 has been determined to be -4.63(10) cm-1. The result is in good agreement with the presently available determination of this level from vibrational spectra.

Elektrisches Dipolmoment von TlBr und TlJ

1971 ◽  
Vol 26 (11) ◽  
pp. 1809-1812 ◽  
Author(s):  
E. Tiemann
Keyword(s):  
Dipole Moment ◽  
Electric Dipole Moment ◽  
Electric Dipole ◽  
Vibrational State ◽  
Stark Effect ◽  
Dipole Moments ◽  
Electric Dipole Moments ◽  
Ground Vibrational State ◽  
Rotational Transitions

Stark-effect measurements on pure rotational transitions of TlBr and Til are described. The derived electric dipole moments of the most abundant isotopic molecules on the ground vibrational state are:205TL79Br : | μ0| = (4.493 ± 0.050) D , 205Tl127 I | μ 0| =(4.607 ± 0.070) D .The electric dipole moment of 205Tl19F | μ 0|=4.2282 (8) D was used as standard.

Elektrisches Dipolmoment und Mikrowellenrotationsspektrum des GeO und GeS

1969 ◽  
Vol 24 (8) ◽  
pp. 1217-1221 ◽  
Author(s):  
J Hoeft ◽  
F.J. Lovas ◽  
E Tiemann ◽  
R Tischer ◽  
T Törring
Keyword(s):  
Electric Dipole ◽  
Vibrational State ◽  
Stark Effect ◽  
Dipole Moments ◽  
Electric Dipole Moments ◽  
Rotational Constants ◽  
Ground Vibrational State ◽  
Rotational Spectra ◽  
Rotational Transitions

Stark-effect measurements on pure rotational transitions of GeO and GeS are described. Measurements on the ground vibrational state of the most abundant isotopic molecules resulted in the following electric dipole moments: 74Ge18O μ = (3,28±0,10) D; 74Ge32S μ = (2,00 + 0,06) D . Due to improved resolution and sensitivity of the spectrometer, the rotational spectra of GeS were measured in more detail and with greater accuracy than previously. The derived rotational constants, Y01 , Y11, Y21 and Y02 , are reported.

Lambda doubling in the infrared spectrum of SH

1984 ◽  
Vol 62 (12) ◽  
pp. 1420-1425 ◽  
Author(s):  
R. J. Winkel Jr. ◽  
Sumner P. Davis
Keyword(s):  
Fourier Transform ◽  
Infrared Spectrum ◽  
Ground State ◽  
Solar Observatory ◽  
Fourier Transform Spectrometer ◽  
Multiplet Splitting ◽  
National Solar Observatory ◽  
Vibration Rotation ◽  
The Fourier Transform ◽  
First Time

The (1–0), (2–1), and (3–2) infrared vibration–rotation bands of the X2Π ground state of sulfur monohydride were observed in emission from a furnace. Multiplet splitting produces two subbands, each of which exhibits lambda splitting. The band heads were observed for the first time, 285 lines were measured, and a calculation of lambda-doubling parameters was made. The spectrum was recorded using the Fourier transform spectrometer at the National Solar Observatory (Kitt Peak).

Spectra of H2–Ar, H2–Kr, and H2–Xe Van der Waals Complexes in Pressure-Induced Infrared Absorption

1971 ◽  
Vol 49 (2) ◽  
pp. 230-242 ◽  
Author(s):  
A. K. Kudian ◽  
H. L. Welsh
Keyword(s):  
Infrared Absorption ◽  
Path Length ◽  
Vibrational State ◽  
Van Der Waals ◽  
Rotational Quantum Number ◽  
Van Der Waals Complexes ◽  
Intermolecular Potential ◽  
Combination Rules ◽  
Ground Vibrational State ◽  
Lennard Jones

Spectra of H2–Ar, H2–Kr, and H2–Xe Van der Waals complexes, accompanying the Q1(0), Q1(1), S1(0), and S1(1) transitions of the pressure-induced fundamental infrared absorption band of hydrogen, have been studied in gas mixtures at 93–180 °K with a path length of 13 m and total pressures of ~3 atm. The main features of the spectra correspond to rotational transitions in the ground vibrational state of the complex, i.e., resolved T and N lines (Δl = ± 3) and unresolved R and P lines (Δl = ± 1), where l is the rotational quantum number of the complex. The spectra are analyzed with eigenvalues derived from the wave-mechanical solution of the isotropic Lennard–Jones 12–6 potential with constants determined from the combination rules for mixed molecular species. Although there is good overall agreement, it is evident that finer details of the spectra will require the introduction of an anisotropic intermolecular potential for their explanation.

A Microwave Fourier Transform Spectrometer in the Range from 18 to 26.4 GHz Increased Sensitivity Using Circular Waveguides. Measurements of Isotopomeres of Carbonylsulfide and of Methane

1991 ◽  
Vol 46 (5) ◽  
pp. 445-449 ◽  
Author(s):  
V. Meyer ◽  
W. Jäger ◽  
R. Schwarz ◽  
H. Dreizler
Keyword(s):  
Fourier Transform ◽  
Natural Abundance ◽  
Fourier Transform Spectrometer ◽  
Increased Sensitivity ◽  
Circular Waveguides ◽  
Rotational Transitions ◽  
Set Up

Abstract We present a microwave Fourier transform spectrometer in the region of 18 to 26.4 GHz with an increase in sensitivity roughly by a factor of ten in comparison to a former set up. Measurements of rotational transitions of isotopomers of carbonylsulfide, OCS, in natural abundance and of rovibrational transitions of methane, CH4, illustrate the improvement

scholarly journals Methyl Internal Rotation and 14N Nuclear Quadrupole Coupling from the Rotational Spectra of Ethyl Isocyanide, iso-Propyl Isocyanide and gauche- and trans-n-Propyl Isocyanide

1992 ◽  
Vol 47 (10) ◽  
pp. 1067-1072 ◽  
Author(s):  
Michael Krüger ◽  
Helmut Dreizler
Keyword(s):  
Fourier Transform ◽  
Internal Rotation ◽  
Vibrational State ◽  
Fourier Transform Spectroscopy ◽  
Coupling Constants ◽  
Ground Vibrational State ◽  
Rotational Spectra ◽  
Barrier Heights ◽  
Quadrupole Coupling ◽  
Nuclear Quadrupole

AbstractThe barrier heights (V3) hindering methyl internal rotation were determined with microwave Fourier transform spectroscopy from the ground vibrational state for the title molecules and found to be V3 = 3.336(52) kcal/mol for ethyl isocyanide, V3 > 3.1 kcal/mol for iso-propyl isocyanide, V3 = 2.894(23) kcal/mol for gauche-n-propyl isocyanide and V3 = 2.954(22) kcal/mol for transn- propyl isocyanide. The quadrupole coupling constants of iso-propyl isocyanide are χaa = 179.3(31) kHz, χbb = -140(15) kHz and χcc - 39(15) kHz; the constants of trans-n-propyl isocyanide were determined to be χaa = 268.1 (71) kHz, χbb = - 108(23) kHz and χcc = - 160(23) kHz.

scholarly journals The Submillimeter-wave Spectrum of the Formaldehyde Isotopomer H2C18O in its Ground Vibrational State

2000 ◽  
Vol 55 (5) ◽  
pp. 486-490 ◽  
Author(s):  
Holger S. P. Müller ◽  
Ralf Gendriesch ◽  
Frank Lewen ◽  
Gisbert Winnewisser
Keyword(s):  
Ground State ◽  
Vibrational State ◽  
Wave Spectrum ◽  
Far Infrared ◽  
Submillimeter Wave ◽  
Spectroscopic Constants ◽  
Published Data ◽  
Rotational Spectrum ◽  
Natural Isotopic Composition ◽  
Ground Vibrational State

Abstract The ground state rotational spectrum of H2C18O has been studied between 485 and 835 GHz with a sample of natural isotopic composition. Additional lines have been recorded around 130 GHz and near 1.85 THz, using a recently developed far-infrared laser-sideband spectrometer. The accurate new line frequencies were fit together with previously published data to obtain greatly improved spectroscopic constants. Both Watson's S and A reduced Hamiltonians have been employed yielding the rotational constants AA = 281 961.215 (82), BA = 36 902.275 51 (36), CA = 32 513.405 89 (36), AA = 281 961.371 (82), BA = 36 904.173 32 (91), and CA = 32 511.524 65 (86) MHz, respectively.

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