A 3Σ–3Π transition of the SiO molecule

1970 ◽  
Vol 48 (12) ◽  
pp. 1436-1440 ◽  
Author(s):  
S. Nagaraj ◽  
R. D. Verma

The spectrum in the region 4200–4300 Å, attributed to the SiO molecule, has been excited strongly in a r.f. discharge through a mixture of argon and a trace of SiCl4 vapor flowing through a quartz tube. The spectrum consists of a single sequence Δν = 0. The 0–0 and 1–1 bands have been photographed at high dispersion. A rotational analysis of these bands shows that they involve a 3Σ–3II transition and not a 1Σ–3Π transition as reported earlier. The following rotational constants were determined:[Formula: see text]


1962 ◽  
Vol 40 (9) ◽  
pp. 1077-1084 ◽  
Author(s):  
T. A. Prasada Rao ◽  
P. Tiruvenganna Rao

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.



1992 ◽  
Vol 70 (5) ◽  
pp. 291-294 ◽  
Author(s):  
Sheila Gopal ◽  
M. Singh ◽  
G. Lakshminarayana

The emission spectrum of Si130Te was excited by microwave discharge (2450 MHz) in a sealed quartz tube. The A1Π–X1Σ+ band system (3100–3900 Å) (1 Å = 10−10 m) photographed under high resolution on a 10.6 m Ebert grating spectrograph. The rotational analysis of 32 bands was carried out, which led to the determination of the accurate vibrational and rotational constants. The rotational structure belonging to ν′ > 9 levels appear to be perturbed.



1977 ◽  
Vol 55 (21) ◽  
pp. 1858-1867 ◽  
Author(s):  
K-E. J. Hallin ◽  
A. J. Merer ◽  
D. J. Milton

S2O has been prepared in a flow system, and various bands at the long wavelength end of the 3400 Å electronic transition photographed in absorption at high dispersion. Rotational analysis of the bands at 3235 and 3278 Å has shown that the bands are type A–B hybrids, with the type A component accounting for nearly all the observed structure. The electronic transition is therefore 1A′–1A′ (ππ*). The rotational constants imply the upper state structure r(S—S) = 2.14 Å, [Formula: see text], with r(S—O) = 1.50 Å (assumed).The vibrational intensity pattern is found to be in agreement with this structure if the electronic origin is placed at 29 696 cm−1 (3367 Å).



1958 ◽  
Vol 36 (11) ◽  
pp. 1526-1535 ◽  
Author(s):  
K. Suryanarayana Rao

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.



1959 ◽  
Vol 37 (2) ◽  
pp. 136-143 ◽  
Author(s):  
Nand Lal Singh

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.



1967 ◽  
Vol 45 (11) ◽  
pp. 3663-3666 ◽  
Author(s):  
K. M. Lal ◽  
B. N. Khanna

The emission spectrum of the A–X system of the PbBr molecule in the region 4 600–5 900 Å has been obtained in the second order of a 21-ft concave grating spectrograph (15 000 lines per inch) with a dispersion of 1.25 Å/mm. A rotational analysis of four bands—(3, 2), (2, 2), (3, 1), and (4, 1)—of this system has been done, leading to the determination of the following rotational constants:[Formula: see text]The system appears to be similar to the A-X system of the PbCl molecule in the visible region, and a [Formula: see text] transition has been suggested.



1966 ◽  
Vol 44 (10) ◽  
pp. 2251-2258 ◽  
Author(s):  
A. E. Douglas ◽  
W. E. Jones

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.



1976 ◽  
Vol 54 (21) ◽  
pp. 2118-2127 ◽  
Author(s):  
K.-E. J. Hallin ◽  
Y. Hamada ◽  
A. J. Merer

Rotational analyses have been carried out for the (0,0) bands of the [Formula: see text] absorption systems of S16O2 and S18O2, from high dispersion plates taken with the gases at dry ice temperature. The rotational analysis of the (0,0) band of S16O2 given by Brand, Jones, and di Lauro is confirmed in general, but their values for the anisotropic electron spin fine structure constants are found to be in error. Our new values remove the discrepancy in the sign of the spin–spin interaction parameter β = E between the gas phase work and the solid state value given by Tinti. This discrepancy had been rationalized by Brand, Jones, and di Lauro in terms of a different choice of phases for the angular momentum operators, but this argument is shown to be incorrect. The spectrum of S18O2 confirms our new values for the spin constants in detail.



1976 ◽  
Vol 54 (13) ◽  
pp. 1343-1359 ◽  
Author(s):  
E. A. Colbourn ◽  
M. Dagenais ◽  
A. E. Douglas ◽  
J. W. Raymonda

The absorption spectrum of F2 in the 780–1020 Å range has been photographed at sufficient resolution to allow a rotational analysis of many bands. A large number of vibrational levels of three ionic states have been observed and their rotational constants determined. Many perturbations in the rotational structure caused by the interaction between the three states have been investigated and the interaction energies determined. The rotational and vibrational structures of a few Rydberg states have also been analyzed in detail but no Rydberg series have been identified. The difficulties in assigning the observed states are discussed. A 1Σu+ – X1Σg+ emission band system has been observed in the 1100 Å region. An analysis of the bands of this system has allowed us to determine the term values and rotational constants of all the vibrational levels of the ground state with ν ≤ 22. The dissociation energy, D0(F2), is found to be greater than 12 830 and is estimated to be 12 920 ± 50 cm−1.



1968 ◽  
Vol 21 (12) ◽  
pp. 2835 ◽  
Author(s):  
AJ McHugh ◽  
DA Ramsay ◽  
IG Ross

The bands of the 3500 Ǻ transition of azulene-do and azulene-ds show two unequal peaks 2.3 cm-l apart, followed by closely spaced fine structure. These bands have been analysed as type A bands of a planar, prolate asymmetric top. Rotational constants for both molecules in the excited state have been determined. The fine structure is due to multiple line coincidences in the high-J, low-K region of the qP branch. To each multiple line can be attributed a running number n = J+m, where m = J-K-1. Given sufficient resolving power, such "lines" should be rather commonly observed in type A and type B bands of large, planar, prolate molecules.



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