SPECTRUM AND STRUCTURE OF THE FREE HNCN RADICAL

1963 ◽  
Vol 41 (2) ◽  
pp. 286-298 ◽  
Author(s):  
G. Herzberg ◽  
P. A. Warsop
Keyword(s):  
Fine Structure ◽  
Ground State ◽  
Electronic Transition ◽  
Flash Photolysis ◽  
Geometrical Structure ◽  
Transition Moment ◽  
Lower State ◽  
State Formula ◽  
Exact Position

A widely spaced perpendicular band at 3440 Å observed in the flash photolysis of diazomethane is ascribed to the free HNCN radical. The study of the fine structure of this band for HNCN, DNCN, and HNC13N has yielded information about the geometrical structure of the molecule in both the upper and lower (ground) state. For the lower state[Formula: see text]The N—C—N group is very nearly linear, but the exact position of the C atom on this line could not be determined. The electronic transition is of the type 2A′–2A″, the transition moment being perpendicular to the plane of the molecule.

SPECTRA AND STRUCTURES OF THE FREE HSiCl AND HSiBr RADICALS

1964 ◽  
Vol 42 (3) ◽  
pp. 395-432 ◽  
Author(s):  
G. Herzberg ◽  
R. D. Verma
Keyword(s):  
Fine Structure ◽  
Band Structure ◽  
Excited States ◽  
Ground State ◽  
Electronic Transition ◽  
Flash Photolysis ◽  
Geometrical Structure ◽  
Lower State ◽  
Triplet Splitting ◽  
Singlet Transition

Intense spectra of HSiCl and HSiBr in the region 6000 to 4100 Å have been obtained in the flash photolysis of SiH3Cl and SiH3Br, both in absorption and in fluorescence. They consist of progressions of bands with very wide K structures and very narrow J structures. A detailed fine structure analysis of these bands has been carried out and the geometrical structure of the molecules in both the upper and the lower states has been established. For the lower state, probably the ground state of HSiCl, it is found that[Formula: see text]and similarly for HSiBr[Formula: see text]In the excited states the angles are appreciably larger (see Table XI).A striking feature of the band structure in both HSiCl and HSiBr is the occurrence of branches of subbands with ΔK = ± 2, in addition to those with ΔK = ± 1 and 0, and furthermore, the presence of a subband with K = 0 in the branch with ΔK = 0. These anomalies can be accounted for by the assumption that the electronic transition is a triplet–singlet transition, more specifically 3A″–1A′ (or possibly 1A′–3A″). However, no triplet splitting has been resolved in the spectrum.

A generalized empirical formula for half-lives of alpha-decay fine structure

2019 ◽  
Vol 28 (08) ◽  
pp. 1950067
Author(s):  
I. Sreeja ◽  
M. Balasubramaniam
Keyword(s):  
Experimental Data ◽  
Fine Structure ◽  
Ground State ◽  
Empirical Formula ◽  
Daughter Nucleus ◽  
Alpha Decay ◽  
Parent Nucleus ◽  
State Formula ◽  
Model Independent ◽  
Proton Radioactivity

A model-independent and [Formula: see text]-dependent four parameter formula has been recently proposed for the studies of one proton and two proton radioactivity. The same form of the formula with different parameter sets worked well for 1p and 2p emission indicating the fact that the similar phenomenological law is able to successfully reproduce both 1p as well as 2p emission half-lives suggesting the identical descriptions of these phenomena. Retaining the same form of the formula, its applicability is studied in this work for calculating the ground state as well as excited state [Formula: see text] emission. For this study, we consider 22 odd–odd nuclei, 31 odd–even nuclei, 52 even–odd nuclei, 88 even–even nuclei with the parent nucleus charge numbers in the range of [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text], respectively. For each of these subsets the emission of [Formula: see text] with different angular momentum values are considered. The general formula with four different parameter sets is proposed and the obtained results are compared with the experimental data. The study reveals that the general form of the proposed empirical formula is suitable for calculating the half-lives of 1p, 2p and [Formula: see text]-emission with different [Formula: see text]-values. With very minimal input like [Formula: see text]-values, and charge number of the daughter nucleus, this formula can be used as a handy tool for a systematic study as well as to plan new experiments.

BAND SPECTRUM AND STRUCTURE OF THE CH+ MOLECULE; IDENTIFICATION OF THREE INTERSTELLAR LINES

1942 ◽  
Vol 20a (6) ◽  
pp. 71-82 ◽  
Author(s):  
A. E. Douglas ◽  
G. Herzberg
Keyword(s):  
Ground State ◽  
Band System ◽  
Lower State ◽  
Band Spectrum ◽  
Interstellar Space ◽  
Molecular Constants ◽  
Vibrational Levels ◽  
State Formula ◽  
Heat Of Dissociation ◽  
Π State

In a discharge through helium, to which a small trace of benzene vapour is added, a new band system of the type 1Π – 1Σ is found which is shown to be due to the CH+ molecule. The R(0) lines of the 0–0, 1–0, and 2–0 bands of the new system agree exactly with the hitherto unidentified interstellar lines 4232.58, 3957.72, 3745.33 Å, thus proving that CH+ is present in interstellar space. At the same time this observation of the band system in absorption shows that the lower state 1Σ is the ground state of the CH+ molecule. The new bands are closely analogous to the 1II – 1Σ+ BH bands. The analysis of the bands leads to the following vibrational and rotational constants of CH+ in its ground state: [Formula: see text], Be″ = 14.1767, αe″ = 0.4898 cm.−1. The internuclear distance is re″ = 1.1310∙10−8 cm. (for further molecular constants see Table V). From the vibrational levels of the upper 1Π state the heat of dissociation of CH+ can be obtained within fairly narrow limits: D0(CH+) = 3.61 ± 0.22 e.v. From this value the ionization potential of CH is derived to be I(CH) = 11.13 ± 0.22 e.v. The bearing of this value on recent work on ionization and dissociation of polyatomic molecules by electron impacts is briefly discussed.

THE 2 700 Å BANDS OF THE N3 MOLECULE

1965 ◽  
Vol 43 (12) ◽  
pp. 2216-2221 ◽  
Author(s):  
A. E. Douglas ◽  
W. Jeremy Jones
Keyword(s):  
Fine Structure ◽  
High Resolution ◽  
Ground State ◽  
Flash Photolysis ◽  
Bond Distance ◽  
Absorption Bands

The 2 700 Å absorption bands found by Thrush in the flash photolysis of HN3 have been studied at high resolution. The rotational fine structure of the strongest band has been analyzed, and it has been shown that the bands arise from a [Formula: see text] transition of the N3 molecule. The bond distance in the ground state of N3 is found to be 1.181 Å.

THE ABSORPTION SPECTRUM OF THE Si2 MOLECULE

1963 ◽  
Vol 41 (1) ◽  
pp. 152-160 ◽  
Author(s):  
R. D. Verma ◽  
P. A. Warsop
Keyword(s):  
Absorption Spectrum ◽  
Dissociation Energy ◽  
Ground State ◽  
Flash Photolysis ◽  
Lower State ◽  
The Third ◽  
Photolysis Apparatus ◽  
Vibrational Constants

Three band systems of Si2 have been found in absorption with a flash photolysis apparatus. Two of the band systems at 3200 and 2100 Å are new, whereas the third is an extension of the 3Σ–3Σ system observed by Douglas in emission. All three systems have the same lower state and arise from [Formula: see text] transitions. It is very probable that the [Formula: see text] state is the ground state of the Si0 molecule. Rotational and vibrational constants of all four 3Σ states have been determined. The dissociation energy of Si2 is estimated to be 3.0 ± 0.2 ev.

The spectrum and structure of the free BH 2 radical

1967 ◽  
Vol 298 (1453) ◽  
pp. 142-159 ◽  
Keyword(s):  
Absorption Spectrum ◽  
Excited State ◽  
Ground State ◽  
Electronic Transition ◽  
Flash Photolysis ◽  
Molecular Constants ◽  
Isotope Shifts ◽  
Geometrical Data

A new absorption spectrum has been found in the flash photolysis of H 3 BCO which, from its structure and the observed isotope shifts can be unambiguously assigned to the free BH 2 radical. The spectrum represents a transition similar to those previously observed in NH 2 and CH 2 . The molecule is linear in the excited state but bent (with an angle of 131°) in the ground state. Molecular constants and geometrical data are evaluated. The electronic transition is 2 B 1 ( II u ) – 2 A 1 and fits well with expectation from the Walsh diagram for X H 2 molecules.

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.

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