The microwave spectrum and molecular structure of trimethylene sulphoxide; bends, tilts and twists in the methylene groups

1977 ◽  
Vol 354 (1679) ◽  
pp. 491-509 ◽  
Keyword(s):  
Excited States ◽  
Ground State ◽  
Rotational Spectrum ◽  
Vibrationally Excited ◽  
Rotational Constants ◽  
Vibrational Ground State ◽  
Isotopic Species ◽  
Microwave Rotational Spectrum ◽  
Methylene Groups ◽  
The Common

The microwave rotational spectrum of the common isotopic species ( 12 CH 2 ) 32 3 S 16 O of trimethylene sulphoxide has been assigned and rotational constants obtained for the vibrational ground state, the first four excited states of the ring puckering mode and two other low-lying vibrationally excited states. In addition rotational constants have been derived for the vibrational ground state of each of the eight different singly substituted isotopic species [ 34 S], [ 13 C 2 ], [13 C 3 ], [ 2 H 2 ], [ 2 H 2 .], [ 2 H 3 ], [ 2 H 3 .] and [ 18 O], with the first three in natural abundance, and are as follows:

scholarly journals The Microwave Spectrum of 3,4-Dihydro-1,2-Pyran

1985 ◽  
Vol 40 (9) ◽  
pp. 913-919
Author(s):  
Juan Carlos López ◽  
José L. Alonso
Keyword(s):  
Dipole Moment ◽  
Excited States ◽  
Ground State ◽  
Principal Axis ◽  
Microwave Spectrum ◽  
Average Intensity ◽  
Ring Conformation ◽  
Vibrationally Excited ◽  
Rotational Constants ◽  
Displacement Measurements

Abstract The rotational transitions of 3,4-dihydro-1,2-pyran in the ground state and six vibrationally excited states have been assigned. The rotational constants for the ground state (A = 5198.1847(24), B = 4747.8716(24) and C = 2710.9161(24) have been derived by fitting μa, μb and μc-type transitions. The dipole moment was determined from Stark displacement measurements to be 1.400(8) D with its principal axis components |μa| =1.240(2), |μb| = 0.588(10) and |μc| = 0.278(8) D. A model calculation to reproduce the ground state rotational constants indicates that the data are consistent with a twisted ring conformation. The average intensity ratio gives vibrational separations between the ground and excited states of the ring-bending and ring-twisting modes of ~ 178 and ~ 277 cm-1 respectively.

scholarly journals Microwave Spectrum and Quadrupole Coupling Constants of 2-Bromothiophene

1975 ◽  
Vol 30 (4) ◽  
pp. 541-548 ◽  
Author(s):  
P. J. Mjöberg ◽  
W. M. Ralowski ◽  
S. O. Ljunggren
Keyword(s):  
Ground State ◽  
Second Order ◽  
Coupling Constants ◽  
Order Perturbation ◽  
Vibrationally Excited ◽  
Rotational Constants ◽  
Isotopic Species ◽  
Principal Axes ◽  
Quadrupole Coupling ◽  
Hyperfine Splittings

Abstract The microwave spectra of the two 79Br and 81Br isotopic species of 2-bromothiophene have been measured in the region 18000-40000 MHz.For both isotopic species, the rotational constants of the ground state and one vibrationally excited state were determined, as well as the centrifugal distortion coefficients of the ground state. The ground state rotational constants in MHz are as follows:C4H332S79Br C4H332S81BrA = 5403.432 ±0.111 5403.563 ±0.095,B = 1139.0689±0.0010 1126.5173±0.0011 C = 940.5142±0.0018 931.9315±0.0009.In order to perform a second-order perturbation treatment of the quadrupole interaction, the matrix elements of products of direction cosines in terms of the symmetric top wave functions have been derived. By the first-and second-order perturbation analysis of the hyperfine splittings of the rotational lines, the nuclear quadrupole coupling constants have been determined. The values in MHz areXaa = 592.7 ±1.5 493.7 ±1.5,Xbb = -295.3 ±0.6 -245.6 ±0.7, Xcc = -297.4 ±1.6 -248.1 ±1.6,Xab = 80 ±9 64±8 ,in the principal axes system of the molecule.

Rotational Spectrum of cis-HS3D

1992 ◽  
Vol 47 (10) ◽  
pp. 1091-1093 ◽  
Author(s):  
M. Liedtke ◽  
A. H. Saleck ◽  
J. Behrend ◽  
G. Winnewisser ◽  
R. Klünsch ◽  
...  
Keyword(s):  
Ground State ◽  
Rotational Spectrum ◽  
Frequency Range ◽  
Rotational Constants ◽  
Vibrational Ground State ◽  
Q 30

AbstractThe rotational spectrum of HS3D in the vibrational ground state has been measured in the frequency range between 75 and 293 GHz. Up to now, about 180 Q-, 30 P-, and 70 R-branch c-type transitions have been identified. The preliminary rotational constants of the species observed support the cis-conformation established earlier from the H2S3 rotational spectrum.

High-Resolution Vibrational Spectra of Furazan

1991 ◽  
Vol 46 (10) ◽  
pp. 841-850
Author(s):  
Otto L. Stiefvater
Keyword(s):  
Excited States ◽  
Ground State ◽  
Double Resonance ◽  
Microwave Spectroscopy ◽  
Statistical Uncertainty ◽  
Molecular Constants ◽  
Vibrationally Excited ◽  
Vibrational Ground State ◽  
Vibrational Bands ◽  
Ft Ir

AbstractThe study by Fourier transform (FT) infrared (IR) spectroscopy of the fundamental vibrational bands v12 and v5 of furazan yields the origins of these bands with a statistical uncertainty of 10-6 cm-1, which leads to an estimated absolute uncertainty of 10-4 cm-1. The values are v°12 = 952.6123 cm -1 and v°5 = 1.005.3536 cm -1. They confirm the values previously deduced from laser/microwave double resonance (LMDR) experiments. Previous results for the molecular constants of the vibrational ground state and of the two vibrationally excited states, as obtained by double resonance modulation (DRM) microwave spectroscopy alone, are confirmed and refined. Advantages brought about through the combination of the DRM microwave and the FT-IR technique are outlined.

Microwave Spectrum of Cyclopentene-3,5-dione

1978 ◽  
Vol 33 (5) ◽  
pp. 581-587 ◽  
Author(s):  
P. J. Mjöberg ◽  
S. O. Ljunggren ◽  
J. E. Bäckvall
Keyword(s):  
Excited States ◽  
Ground State ◽  
Microwave Spectrum ◽  
Frequency Region ◽  
Bending Vibration ◽  
Rotational Constants ◽  
Ring Configuration ◽  
Vibrational Ground State ◽  
Straight Line ◽  
Ring Puckering

The microwave spectra of cyclopentene-3,5-dione in the ground state and the first four excited states of the ring bending vibration have been studied in the frequency region 26.5 to 40.0 GHz and the corresponding rotational constants have been determined. The ground state spectrum of one isotopically substituted species, 4-deuteriocyclopentene-3,5-dione, has also been assigned. The following values of the ground state rotational constants (MHz) were obtained from the spectra:From intensity and inertial-defect considerations the ring configuration was shown to be planar in the ground state. In addition, the nearly straight-line behaviour of the rotational constants as functions of the ring-puckering vibrational quantum number indicates that the ring-puckering vibration is nearly harmonic with a fundamental frequency of approximately 90 cm-1 . The electric dipole moment for the unsubstituted species in the vibrational ground state was found to be 1.680 ± 0.009 Debye units

THE HYDROGEN–CHLORINE SYSTEM IN THE MM PRESSURE RANGE II. THE VIBRATIONAL GROUND STATE STUDIED BY SELF-ABSORPTION

1964 ◽  
Vol 42 (10) ◽  
pp. 2193-2200 ◽  
Author(s):  
J. R. Alrey ◽  
F. D. Findlay ◽  
J. C. Polanyi
Keyword(s):  
Excited States ◽  
Relative Intensity ◽  
Ground State ◽  
Pressure Range ◽  
Infrared Emission ◽  
Absolute Amount ◽  
Reaction Products ◽  
Vibrationally Excited ◽  
Vibrational Ground State ◽  
Apparent Deviation

Studies of energy distribution among reaction products, through the agency of infrared chemiluminescence, have previously only yielded information concerning the distribution among vibrationally excited states. In the work described here it was shown that self-absorption of the infrared emission could be used as a measure both of the relative and the absolute amount of product present in the vibrational ground state, ν = 0. Two independent methods were used to measure the extent of self-absorption. The first method relied on measurements of an apparent deviation from Boltzmann-type rotational intensity distribution within the ν(1–0) and ν(2–1) bands. The second method depended on measurements of an apparent deviation of the relative intensity of corresponding H35Cl and H37Cl isotopic lines from the natural abundance ratio. (It was shown, at the same time, that the isotopic reactions H + 35Cl2 → H35Cl + 35Cl and H + 37Cl2 → H37Cl + 37Cl have the same rate constant, within ±10%). A third method of measuring the extent of self-absorption, which depends on the detection of an anomaly in the relative intensity of P- and R-branch emission lines is discussed.The self-absorption method was applied to the study of the hydrogen–chlorine system in the 1–2 mm Hg pressure range (see also Part I). Mean partial pressures of HClν=0 ~ 10−2 mm Hg were measured in individual rotational states to an accuracy of ca. ±10%, using an optical path length of 20 cm. The rotational distribution in ν = 0 corresponded to a temperature of 1150 ± 150 °K (the uncertainty in this figure encompasses two independent methods of estimating the self-absorption), as compared with 1300 ± 100 °K for all vibrationally excited states (Part I).

Microwave Spectrum and Quadrupole Coupling Constants of Orthochloropyridine

1972 ◽  
Vol 27 (6) ◽  
pp. 1011-1014 ◽  
Author(s):  
F Scappini ◽  
A Guarnieri
Keyword(s):  
Ground State ◽  
Microwave Spectrum ◽  
Coupling Constants ◽  
Rotational Spectrum ◽  
Rotational Constants ◽  
Vibrational Ground State ◽  
Quadrupole Coupling ◽  
Nuclear Quadrupole

Abstract The rotational spectrum of 2-chloropyridine was measured in the region between 8-40 GHz. The rotational constants for the vibrational ground state are: A = 5872.01 ± 0.02 MHz, B = 1637.82 ± 0.02 MHz, C=1280.51 ± 0.02 MHz. The value 0.0385 amu · A2 of the inertia defect indicates a planar nuclear frame. From the hyper-fine splittings of the rotational lines the nuclear quadrupole coupling constants of 35Cl were determined. The values are:χaa = 70.79 ± 0.17 MHz, χbb = 39.01 ± 0.45 MHz, χcc = 31.78 ± 0.62 MHz.

Extended Analysis of the Rotational Spectrum of HCCF

1989 ◽  
Vol 44 (2) ◽  
pp. 131-138 ◽  
Author(s):  
F. Rohwer ◽  
R. Hinze ◽  
A. Guarnieri
Keyword(s):  
Excited States ◽  
Ground State ◽  
Microwave Spectrum ◽  
Frequency Region ◽  
Rotational Spectrum ◽  
Bending Vibrations ◽  
Rotational Constants ◽  
Extended Analysis

Abstract The microwave spectrum of fluoroacetylene (HCCF) has been measured in the frequency region 35 -260 GHz. Rotational constants of the ground state and rotational as well as rotation-vibrational interaction constants of several excited states of the C - C - H (ν4) and the C - C - F (ν5) bending vibrations have been obtained.

Terahertz Spectrum of Trioxane

1996 ◽  
Vol 51 (1-2) ◽  
pp. 123-128 ◽  
Author(s):  
H. Klein ◽  
S. P. Belov ◽  
G. Winnewisser
Keyword(s):  
Ground State ◽  
Rotational Constant ◽  
Rotational Spectrum ◽  
Centrifugal Distortion ◽  
Frequency Range ◽  
Experimental Accuracy ◽  
Terahertz Spectrum ◽  
Vibrational Ground State ◽  
Isotopic Species ◽  
Centrifugal Distortion Constants

Abstract The pure rotational spectrum of trioxane, (H2CO)3 the trimer of formaldehyde, has been recorded with high resolution in the frequency range between 326 and 947 GHz for the main isotopomer, the 13 C, and the 18O isotopic species in the vibrational ground state. These new high J and K data reveal that the molecule is fairly rigid. For the constants determinable from the recorded high J and K spectra (J = 90 and K = 75) the rotational constant B = 5273.257 180(33) MHz,the two quartic centrifugal distortion constants DJ, and DJK, and the three sextic constants HJ, HJK, and HKJ are needed in the fit to reproduce the measured spectra within experimental accuracy. In addition, for the 13C isotopomer the sextic constants HJK and HKJ are determined as well as the off-diagonal parameters d1 and d2.

Excited-State Dynamics in the RNA Nucleotide Uridine 5’-Monophosphate Investigated by Femtosecond Broadband Transient Absorption Spectroscopy

2019 ◽  
Author(s):  
Matthew M. Brister ◽  
Carlos Crespo-Hernández
Keyword(s):  
Excited State ◽  
Excited States ◽  
Ground State ◽  
Transient Absorption ◽  
Electronic Energy ◽  
Transient Absorption Spectroscopy ◽  
Electronic Relaxation ◽  
Vibrationally Excited ◽  
Excited State Dynamics ◽  
Π State

<p></p><p> Damage to RNA from ultraviolet radiation induce chemical modifications to the nucleobases. Unraveling the excited states involved in these reactions is essential, but investigations aimed at understanding the electronic-energy relaxation pathways of the RNA nucleotide uridine 5’-monophosphate (UMP) have not received enough attention. In this Letter, the excited-state dynamics of UMP is investigated in aqueous solution. Excitation at 267 nm results in a trifurcation event that leads to the simultaneous population of the vibrationally-excited ground state, a longlived <sup>1</sup>n<sub>O</sub>π* state, and a receiver triplet state within 200 fs. The receiver state internally convert to the long-lived <sup>3</sup>ππ* state in an ultrafast time scale. The results elucidate the electronic relaxation pathways and clarify earlier transient absorption experiments performed for uracil derivatives in solution. This mechanistic information is important because long-lived nπ* and ππ* excited states of both singlet and triplet multiplicities are thought to lead to the formation of harmful photoproducts.</p><p></p>

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