New emission band systems of the NH+ molecule

1968 ◽  
Vol 46 (1) ◽  
pp. 61-73 ◽  
Author(s):  
R. Colin ◽  
A. E. Douglas
Keyword(s):  
Radio Astronomy ◽  
Ground State ◽  
Emission Band ◽  
Single Band ◽  
Absorption Lines ◽  
High Dispersion ◽  
Rotational Constants ◽  
Interstellar Absorption ◽  
Isotopic Species ◽  
Π State

Two new band systems of the NH+ molecule have been photographed at high dispersion and analyzed. One system consists of a single band at 4348.5 Å which arises from a 2Δ–2Π transition and the second consists of three bands of a 2Σ−–2Π transition with the strongest (0–0) band lying at 4628.9 Å. A number of the vibrational and rotational constants of these states have been determined. From a study of the isotopic species 14NH+, 15NH+, and 14ND, it has been established that the ground state of NH+ is the 2Π state and that a 4Σ− state lies 354 cm−1 higher. The spectrum has allowed us to determine the wavelengths at which cometary spectra and interstellar absorption lines of NH+ are expected to fall and to predict that the transition between the two lowest levels, which may be of interest to radio astronomy, occurs at 13 500 mc/s.

THE SPECTRUM OF SILICON HYDRIDE

1957 ◽  
Vol 35 (1) ◽  
pp. 71-77 ◽  
Author(s):  
A. E. Douglas
Keyword(s):  
Dissociation Energy ◽  
Band System ◽  
Absorption Lines ◽  
High Dispersion ◽  
Silicon Hydride ◽  
Rotational Constants ◽  
Interstellar Absorption

The 0–0, 1–0, 2–1, and 2–2 bands of the 2Δ–2Π band system of SiH have been photographed under high dispersion and analyzed. The vibrational and rotational constants have been determined and the dissociation energy has been found to be 3.19 ± 0.25 ev. A list of SiH lines which may occur as interstellar absorption lines is given.

ROTATIONAL ANALYSIS OF THE β BANDS OF PHOSPHORUS MONOXIDE

1959 ◽  
Vol 37 (2) ◽  
pp. 136-143 ◽  
Author(s):  
Nand Lal Singh
Keyword(s):  
Ground State ◽  
Band System ◽  
Electronic States ◽  
Rotational Analysis ◽  
Rotational Constants ◽  
Fine Structures ◽  
Π State

The fine structures of three of the β bands of PO which occur near 3200 Å have been analyzed. The analysis shows that the upper state of this band system is a 2Σ and not a 2Π state as previously believed. The rotational constants of both electronic states have been determined and it is found that the ground state constants, previously determined from the γ bands, are incorrect.

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.

PREDISSOCIATIONS OF THE C12O AND C13O MOLECULES

1955 ◽  
Vol 33 (3-4) ◽  
pp. 125-132 ◽  
Author(s):  
A. E. Douglas ◽  
C. K. Møller
Keyword(s):  
Ground State ◽  
Good Evidence ◽  
High Dispersion ◽  
Dissociation Limit ◽  
Π State

The Ångström bands of C12O and C13O have been photographed with a high dispersion spectrograph and the predissociations previously reported in these bands have been re-examined. The predissociations provide good evidence that C12O has a dissociation limit 89595 ± 30 cm.−1 above the ν = 0 level of the ground state. The fourth positive (A1Π − X1Σ) bands have been re-examined and it has been shown that, contrary to earlier reports, there is no evidence for predissociation in the A1Π state.

ULTRAVIOLET SPECTRA OF LiH AND LiD

1957 ◽  
Vol 35 (10) ◽  
pp. 1204-1214 ◽  
Author(s):  
R. Velasco
Keyword(s):  
Excited State ◽  
Ground State ◽  
Band System ◽  
Electronic States ◽  
High Dispersion ◽  
Dissociation Energies ◽  
Near Ultraviolet ◽  
Path Lengths ◽  
Vibrational Constants ◽  
Π State

The absorption spectra of LiH and LiD have been observed in the near ultraviolet with high dispersion and absorbing path lengths up to 16 meters. A new band system has been found in each molecule involving the ground state and a 1Π excited state. Rotational and vibrational analyses of this system have been carried out and rotational and vibrational constants for the upper state have been determined. The observed breaking off of the rotational structure of the bands of this B1Π—X1Σ+ system has been interpreted as due to predissociation by rotation. With this assumption very accurate dissociation limits of the B1Π state have been obtained. From these dissociation limits the dissociation energies of the three known electronic states of LiH and LiD have been calculated. In particular the dissociation energies (D0) of the ground states of LiH and LiD have been found to be 2.4288 ± 0.0002 ev. and 2.4509 ± 0.0010 ev., respectively.

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:

EMISSION BAND SPECTRA OF NITROGEN THE LYMAN-BIRGE-HOPFIELD SYSTEM

1956 ◽  
Vol 34 (8) ◽  
pp. 780-789 ◽  
Author(s):  
Alf Lofthus
Keyword(s):  
Raman Spectrum ◽  
High Resolution ◽  
Emission Spectrum ◽  
Ground State ◽  
Emission Band ◽  
Equilibrium Constants ◽  
Rotational Constants ◽  
Near Ultraviolet ◽  
Band Spectra

The near ultraviolet part of the emission spectrum of nitrogen has been photographed under high resolution. Thirteen bands of the [Formula: see text] system (Lyman–Birge–Hopfield) have been analyzed and new vibrational and rotational constants obtained. Combining the observed data with those obtained by Stoicheff from the Raman spectrum of nitrogen, refined equilibrium constants for the ground state were obtained. The predissociation in the α1Πg state was observed.

ROTATIONAL ANALYSIS OF THE γ SYSTEM OF THE PO MOLECULE

1958 ◽  
Vol 36 (11) ◽  
pp. 1526-1535 ◽  
Author(s):  
K. Suryanarayana Rao
Keyword(s):  
Ground State ◽  
Electronic Transition ◽  
Lower State ◽  
High Dispersion ◽  
Rotational Analysis ◽  
Small Perturbations ◽  
Rotational Constants ◽  
The One

The bands of the γ system of the PO molecule have been photographed under high dispersion (0.35 Å/mm). A rotational analysis of the 0–0, 0–1, and 1–0 bands is given, which differs from the one previously given by Sen Gupta. In addition, four more bands, namely, the 1–2, 2–1, 2–3, and 2–4 bands, have been analyzed. The bands are attributed to the electronic transition, A3Σ–X2Πreg, the lower state being the ground state of the molecule. The new rotational constants for the ground state are the following:[Formula: see text]The spin doubling in the upper state is small. Perturbations in the v = 0 level of the upper state, which were not reported previously, are observed and discussed. They supply a welcome confirmation of the correctness of the analysis here presented.

scholarly journals Near-UV nebular absorption lines of η Carinae

2003 ◽  
Vol 212 ◽  
pp. 196-197
Author(s):  
Theodore R. Gull ◽  
Gladys L. Vieira ◽  
Anthony C. Danks
Keyword(s):  
Energy Level ◽  
Ground State ◽  
Energy Levels ◽  
Absorption Lines ◽  
Resolving Power ◽  
Line Of Sight ◽  
Interstellar Absorption ◽  
Multiple Components ◽  
Ground Energy ◽  
Η Car

The notorious η Carinae was observed with the stis from 2380 Å to 3160 Å with a resolving power of ~ 130000. Over 500 absorption lines have been identified as originating from Fe i, Fe ii, Ti ii, V ii, Cr ii, Ni ii, Co ii, Mn ii, Mg i and Mg ii. Most of the lines have multiple components ranging from −145kms–1, –385kms–1 to –587kms–1. Many interstellar absorption velocity systems, also found in the spectra of other Carina stars, are seen in the spectrum of η Car. While ISM absorption lines originate from the ground energy level, the nebular lines originate from energy levels well above the ground state. We are still evaluating the origin and location of these velocity systems in line of sight.

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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