The Ground State and A2Π Excited State of Magnesium Deuteride

1975 ◽  
Vol 53 (15) ◽  
pp. 1477-1482 ◽  
Author(s):  
Walter J. Balfour ◽  
Hugh M. Cartwright
Keyword(s):  
Excited State ◽  
High Resolution ◽  
Emission Spectrum ◽  
Isotope Effect ◽  
Ground State ◽  
Visible Emission ◽  
Molecular Constants ◽  
Dissociation Energies ◽  
First Time ◽  
Π State

The visible emission spectrum of MgD has been reexamined at high resolution. Published analyses of the A2Π → X2Σ+ system have been extended and the data have been combined with observations in the B′2Σ+ → X2Σ+ system to provide information on the ground state levels ν = 3, 4, 5, and 6 for the first time. The following molecular constants (in cm−1) have been determined—for the A2Π state: ωc = 1154.75, ωcxc = 16.675, Bc = 3.2190, Dc = 9.64 × 10−5 and for the X2Σ+ state: ωc = 1077.71, ωcxc = 15.92, Bc = 3.0306, and Dc = 9.39 × 10−5. The dissociation energies in the A2Π and X2Σ+ states have been estimated to be ~ 15 500 cm−1 and ~ 11 500 cm−1 respectively. The MgH/MgD isotope effect and the Λ doubling in the A2Π state are discussed.

Rotational Analysis of the lΠ–XlΣ+ System of C80Se

1974 ◽  
Vol 52 (9) ◽  
pp. 813-820 ◽  
Author(s):  
René Stringat ◽  
Jean-Paul Bacci ◽  
Marie-Hélène Pischedda
Keyword(s):  
Emission Spectrum ◽  
Ground State ◽  
High Frequency ◽  
Rotational Analysis ◽  
Molecular Constants ◽  
High Frequency Discharge ◽  
Perturbed State ◽  
Simple Evaluation ◽  
Π State

The strongly perturbed 1Π–X1Σ+ system of C80Se has been observed in the emission spectrum of a high frequency discharge through selenium and carbon traces in a neon atmosphere. The analysis of five bands yields, for the molecular constants of the ground state, the values Be″ = 0.5750 cm−1, [Formula: see text], αe″ = 0.00379 cm−1, re″ = 1.676 Å, ΔG″(1/2) = 1025.64 cm−1, and ΔG″(3/2) = 1015.92 cm−1. The numerous perturbations in the 1Π state prohibit the simple evaluation of the constants of the perturbed state and of the perturbing ones.

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.

High resolution emission spectrum of H2 between 78 and 118 nm

1984 ◽  
Vol 62 (12) ◽  
pp. 1686-1705 ◽  
Author(s):  
Jean-Yves Roncin ◽  
Françoise Launay ◽  
Michel Larzilliere
Keyword(s):  
High Resolution ◽  
Emission Spectrum ◽  
Appreciable Amount ◽  
Molecular Constants ◽  
Strong Emission ◽  
Reported Data ◽  
Quantum Defect Theory ◽  
First Time ◽  
Line Positions ◽  
Absorption Features

The complete high resolution emission spectrum of molecular hydrogen is obtained for the first time in the range 78–118 nm. A uniform set of data is derived from accurate line positions of the (unperturbed) Q branches of the C, D, D′, and [Formula: see text] transitions. Molecular constants fitted for both the ground state and the excited states of symmetry [Formula: see text] are obtained. For the latter case, they are compared with ab initio and multichannel quantum defect theory (MQDT) calculations. Self-absorption features indicate the production, in an appreciable amount, of H2(ν″ = 1) in the discharge. The reported data were not available to laser physicists and also astrophysicists who have observed strong emission lines of H2 from the atmospheres of Jupiter and Saturn.

AN EMISSION SPECTRUM OF THE DIACETYLENE ION: A STUDY OF SCHÜLER'S "T" SPECTRUM UNDER HIGH RESOLUTION

1956 ◽  
Vol 34 (10) ◽  
pp. 1046-1074 ◽  
Author(s):  
J. H. Callomon
Keyword(s):  
Excited State ◽  
High Resolution ◽  
Emission Spectrum ◽  
Organic Compounds ◽  
Ground State ◽  
Inert Gas ◽  
Vibrational Assignments ◽  
First Excited State ◽  
Helium Discharge ◽  
Very High

Schüler and Reinebeck have described a new spectrum which was observed in a discharge through a mixture of an inert gas and the vapor of any of a number of organic compounds. This spectrum was labelled "T". Further experiments by the authors provided evidence that the carrier of the "T" spectrum was the diacetylene molecule. The "T" spectrum has now been reinvestigated using both normal and fully deuterated diacetylenes in a helium discharge and photographed on grating instruments with very high resolving powers. Previous vibrational assignments were extended, and the rotational structure was completely analyzed in four bands. The results, together with other evidence, show that the carrier of the "T" spectrum is the diacetylene ion, C4H2+. The vibrational and rotational constants differ but little from those of the diacetylene ground state. The spectrum involves a transition between the first excited state A2Πu(i) and the ground state X2Πg(i) of the ion and is analogous in detail to the well-known Fox, Duffendack, and Barker system of CO2+.

A new predissociated 2Σ+ state of the BeCl molecule

1977 ◽  
Vol 55 (6) ◽  
pp. 582-588 ◽  
Author(s):  
M. Carleer ◽  
B. Burtin ◽  
R. Colin
Keyword(s):  
Excited State ◽  
High Resolution ◽  
Dissociation Energy ◽  
Intensity Distribution ◽  
Internuclear Distance ◽  
Ground State ◽  
Thermochemical Data ◽  
Molecular Constants ◽  
Equilibrium Internuclear Distance ◽  
A Value

Ten bands belonging to a new B2Σ+–X2Σ+ system of the BeCl molecule have been discovered in emission between 1990 and 2175 Å. The bands of both isotopes Be35Cl and Be37Cl have been photographed at high resolution and the most intense ones have been rotationally analyzed. Only three levels of the excited state have been observed and they present vibrational and rotational perturbations. The principal molecular constants of the new B2Σ+ state of Be35Cl are: v00 = 48 827.6, ΔG1/2 = 925.5, ΔG3/2 = 1212.7, Be = 0.7751, De = 3.5 × 10−6 cm−1, and the equilibrium internuclear distance is 1.7422 Å. The unusual intensity distribution in the bands can be tentatively interpreted as the result of an inverse predissociation which leads to a value of D″0 = 27 800 ± 500 cm−1 (3.45 ± 0.06 eV) for the dissociation energy of the ground state of the BeCl molecule. This value is at variance with thermochemical data.

The A–X system of the CuCl molecule

1981 ◽  
Vol 59 (2) ◽  
pp. 289-297 ◽  
Author(s):  
G. P. Mishra ◽  
S. B. Rai ◽  
K. N. Upadhya
Keyword(s):  
High Resolution ◽  
Ground State ◽  
Electronic Transition ◽  
Band System ◽  
Rotational Structure ◽  
Molecular Constants ◽  
X Band ◽  
Standard Deviations ◽  
Concave Grating ◽  
Π State

The A–X band system of CuCl has been photographed in emission under high resolution in the 2nd order of a 10.6 m concave grating spectrograph. Rotational structure in four bands, viz. (1,0), (0,0), (0,1), and (1,2) has been analysed. The present analysis confirms that in the A–X system the electronic transition involved is 1Π–1Σ where 1Σ is the ground state of the molecule. The Λ-type doubling in the 1Π state is found to be appreciable. The molecular constants for the excited A state of 63Cu35Cl are (with standard deviations in parentheses): Be = 0.168432(7) cm−1; αe = 0.001067(7); De = 0.1134(11) × 10−6; q = 0.000871(9); qD = 0.85(18) × 10−8; ν10 = 19 500.271(8); ν00 = 18 999.104(7); ν01 = 18 579.735(10); and ν12 = 18 574.745(11).

A high resolution study of A1Π–X1Σ transition of the PN molecule

1981 ◽  
Vol 59 (11) ◽  
pp. 1640-1652 ◽  
Author(s):  
S. N. Ghosh ◽  
R. D. Verma ◽  
J. VanderLinde
Keyword(s):  
High Resolution ◽  
Emission Spectrum ◽  
Spectral Region ◽  
Rotational Analysis ◽  
Molecular Constants ◽  
Medium Resolution ◽  
Π State ◽  
Resolution Study

The emission spectrum of PN has been rephotographed at high resolution in the spectral region 2200 to 3100 Å. The bands analyzed involve ν′ = 0–10 to ν″ = 0–11 transitions of the A1Π–X1Σ+ system of which only a few of the strongest bands have previously been reported at low and medium resolution. From a rotational analysis of the spectrum, new perturbations in the ν′ = 0, 2, 3, and 7 levels of they'll have been observed. A deperturbation study of these levels as well as a previously reported perturbation in the ν′ = 1 identify the perturbing states as 3Δ perturbing A1Π, ν = 0 and 3Σ− perturbing A1Π, ν = 2 and 3; both states arising from the 1π42π37σ23π configuration. Molecular constants for the perturbing states are obtained in addition to improved molecular constants for the A1Π state.

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>

Ground state molecular parameters of phosphine, PH3, from the simultaneous analysis of the high-resolution infrared, microwave and submillimeterwave spectra

1985 ◽  
Vol 50 (11) ◽  
pp. 2480-2492 ◽  
Author(s):  
Soňa Přádná ◽  
Dušan Papoušek ◽  
Jyrki Kauppinen ◽  
Sergei P. Belov ◽  
Andrei F. Krupnov ◽  
...  
Keyword(s):  
Fourier Transform ◽  
High Resolution ◽  
Ground State ◽  
Unitary Transformation ◽  
Point Of View ◽  
Acoustic Detection ◽  
Molecular Parameters ◽  
Microwave Spectrometer ◽  
Fourier Transform Spectra ◽  
First Time

Fourier transform spectra of the ν2 band of PH3 have been remeasured with 0.0045 cm-1 resolution. Ground state combination differences from these data have been fitted simultaneously with the microwave and submillimeterwave data to determine the ground state spectroscopical parameters of PH3 including the parameters of the Δk = ± 3n interactions. The correlation between the latter parameters has been discussed from the point of view of the existence of two equivalent effective rotational operators which are related by a unitary transformation. The ΔJ = 0, +1, ΔK = 0 (A1 ↔ A2, E ↔ E) rotational transitions in the ν2 and ν4 states have been measured for the first time by using a microwave spectrometer and a radiofrequency spectrometer with acoustic detection.

High resolution spectrum of GdO

1976 ◽  
Vol 54 (24) ◽  
pp. 2429-2434 ◽  
Author(s):  
B. R. Yadav ◽  
S. B. Rai ◽  
D. K. Rai
Keyword(s):  
High Resolution ◽  
Emission Spectrum ◽  
Visible Emission ◽  
High Resolution Spectrum ◽  
First Order ◽  
Isotopic Shifts ◽  
Vibrational Constants ◽  
Dc Arc

The visible emission spectrum of the GdO molecule has been produced in a DC arc source and has been photographed in the first order of a 10.6 m grating spectrograph. Bands are shown to have a six-headed structure and improved vibrational constants have been obtained in this study. Isotopic shifts have been calculated for the various isotopic molecules. Tentative suggestions regarding the nature of the transition have been made.

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