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.

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.

ROTATIONAL ANALYSIS OF THE VISIBLE BAND SYSTEM OF THE BiF MOLECULE

1962 ◽  
Vol 40 (9) ◽  
pp. 1077-1084 ◽  
Author(s):  
T. A. Prasada Rao ◽  
P. Tiruvenganna Rao
Keyword(s):  
Band System ◽  
High Dispersion ◽  
Rotational Analysis ◽  
Rotational Constants ◽  
Visible Band ◽  
System A

A rotational analysis of five bands, (1,0), (0,0), (0,1), (0.2), and (0,3), of the visible band system A of BiF has been carried out by photographing the bands under high dispersion (1.25 Å/mm). The analysis has shown that the bands arise from a 0+(3Σ−)–0+(3Σ−) transition. The rotational constants for the upper and lower states of the system are obtained.

ABSORPTION SPECTRUM OF THE NO MOLECULE: IV. THE G2Σ−–X2Π SYSTEM

1964 ◽  
Vol 42 (5) ◽  
pp. 848-859 ◽  
Author(s):  
A. Lofthus ◽  
E. Miescher
Keyword(s):  
Absorption Spectrum ◽  
Dissociation Energy ◽  
Band System ◽  
The Other ◽  
High Dispersion ◽  
Electron Configuration ◽  
The Many ◽  
No Absorption ◽  
Overlapping Bands

High-dispersion plates of the NO absorption spectrum have been studied between 1600 and 1390 Å for the three isotopic molecules N14O16, N15O16, and N14O18, and G2Σ−–X2Π bands were sorted out from the many overlapping bands in the spectrum. The well-defined band system satisfies the established isotope relations. In contrast with most of the other known NO band systems G2Σ−–X2Π shows almost no perturbations. Vibrational and rotational analyses gave the following constants for the G2Σ− state of N14O16: Te = 62911.7 cm−1; ωe = 1085.54 cm−1, ωexe = 11.083 cm−1, ωeye = −0.1439 cm−1, Be = 1.2523 cm−1, αe = 0.0204 cm−1, γe = 1.3426 Å. The combination defect observed in the G2Σ−–X2Π bands agrees with the defect found in the A2Σ+–X2Π(γ) bands except in sign, which is opposite. Therefore, the symmetry of the G state is confirmed as 2Σ−. The "pure precession" relation between G2Σ− and X2Π is found to hold for the Λ-type doubling of X2Π. The diffuse structure of the band assigned to ν = 10 indicates that G2Σ− is predissociated by a repulsive 2Σ− state dissociating into 2D(N)+3P(O) atoms at 71660 cm−1. The dissociation energy and electron configuration for G2Σ− are discussed.

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.

THE ABSORPTION SPECTRUM OF CF2

1967 ◽  
Vol 45 (7) ◽  
pp. 2355-2374 ◽  
Author(s):  
C. Weldon Mathews
Keyword(s):  
Absorption Spectrum ◽  
Electronic State ◽  
Ground State ◽  
Band System ◽  
Electronic States ◽  
Vibrational Structure ◽  
Rotational Structure ◽  
Transition Moment ◽  
High Dispersion ◽  
Parallel Type

The absorption spectrum of CF2 in the 2 500 Å region has been photographed at high dispersion, and the rotational structure of a number of bands has been analyzed. The analysis of the well-resolved subbands establishes that these are perpendicular- rather than parallel-type bands, as previously assigned. Further analysis shows that the upper and lower electronic states are of 1B1 and 1A1symmetries respectively, corresponding to a transition moment that is perpendicular to the plane of the molecule. In the upper electronic state, r0(CF) = 1.32 Å and [Formula: see text], while in the ground state, r0(CF) = 1.300 Å and [Formula: see text]. An investigation of the vibrational structure of the band system has shown that the vibrational numbering in ν2′ must be increased by one unit from earlier assignments, thus placing the 000–000 band near 2 687 Å (37 220 cm−1). A search between 1 300 and 8 500 Å showed two new band systems near 1 350 and 1 500 Å which have been assigned tentatively to the CF2 molecule.

scholarly journals 10. Radio observations of interstellar neutral hydrogen clouds

1957 ◽  
Vol 4 ◽  
pp. 66-66
Author(s):  
R. S. Lawrence
Keyword(s):  
Angular Resolution ◽  
Neutral Hydrogen ◽  
Optical Component ◽  
Absorption Lines ◽  
Radio Observations ◽  
Interstellar Absorption ◽  
Peak Intensity

The detailed relationship between optical interstellar absorption lines and 21-cm. observations is investigated in this paper.Dr Guido Münch, of the Mount Wilson and Palomar Observatories, provided the list of six intermediate-latitude stars shown in Table 1. The spectra of these stars all show complex absorption lines due to interstellar Ca 11. The 21-cm. line is measurable in four of the six regions, although the peak intensity is low in each case. It is noteworthy that for the first two stars on the list the radio velocity agrees closely with the velocity of an intense optical component. In view of the great difference in angular resolution, the failure to find correspondence in every case is not surprising.

The b1Σ+–X3Σ− band system of SO

1968 ◽  
Vol 46 (13) ◽  
pp. 1539-1546 ◽  
Author(s):  
R. Colin
Keyword(s):  
High Resolution ◽  
Microwave Discharge ◽  
Band System ◽  
Rotational Constants

The 0–0, 1–1, 2–2, and 0–1 bands of the b1Σ+–X3Σ− transition of the SO molecule have been observed in the afterglow produced when COS + O2 is pumped rapidly through a microwave discharge. The two strongest bands, 0–0 and 1–1, which lie respectively at 9549.08 and 9626.13 Å, have been photographed at high resolution and have been analyzed. Using the known X3Σ− rotational constants, the vibrational and rotational constants of the 1Σ+ state (Tc = 10 509.97 cm−1) have been determined: ωc′ = 1067.66 cm−1, Bc′ = 0.70262 cm−1, and rc′ = 1.5005 Å. Rotational intensity distributions for 1Σ+–3Σ− transitions are discussed. The a1Δ state of SO is predicted to lie at T ~ 6350 cm−1.

THE b1Σ+–X3Σ− BAND SYSTEM OF NF

1966 ◽  
Vol 44 (10) ◽  
pp. 2251-2258 ◽  
Author(s):  
A. E. Douglas ◽  
W. E. Jones
Keyword(s):  
Ground State ◽  
Band System ◽  
High Dispersion ◽  
Rotational Analysis ◽  
Strong Band

If argon mixed with a small amount of NF3 is pumped rapidly through a mild discharge, a green glow is observed downstream from the discharge. This emission has been photographed with a high dispersion spectrograph and found to consist of a strong band with a head at 5 288 Å and a number of weaker bands. A rotational analysis of the bands has shown that they are the b1Σ+–X3Σ− bands of the NF molecule. The constants of the two states have been determined and it is found that for the ground state, ωe = 1 141.37 cm−1 and re = 1.317 3 Å.

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