A note on the rotational analysis of the A–X system of the PbBr molecule

1968 ◽  
Vol 46 (17) ◽  
pp. 1991-1992
Author(s):  
K. M. Lal ◽  
B. N. Khanna

The rotational structure of the A–X system of the PbBr molecule has been recorded in the second order of a 35-ft concave grating spectrograph at a dispersion of 0.33 Å/mm and the analysis of four bands (3, 2), (2, 2), (4, 2), and (4, 1) has been done. In all, four branches have been observed for each of the bands and they have been explained as the P and R branches due to Pb79Br and Pb18Br. The following constants were obtained:[Formula: see text]

1964 ◽  
Vol 42 (4) ◽  
pp. 690-695 ◽  
Author(s):  
K. Madhusudana Rao ◽  
P. Tiruvenganna Rao

The rotational structure of the (0, 0), (0, 1), (0, 2), and (1, 0) bands of the visible band system (A–X1) of PbF has been examined in the second order of a 21-ft concave grating spectrograph having a dispersion of 1.25 Å/mm. A rotational analysis of the bands has led to a determination of the rotational constants of the upper and lower states. From consideration of electron configurations it is suggested that the system arises from a [Formula: see text] transition which is a case c equivalent of [Formula: see text].


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.


1972 ◽  
Vol 50 (18) ◽  
pp. 2206-2210 ◽  
Author(s):  
O. Nath Singh ◽  
I. S. Singh ◽  
O. N. Singh

The rotational analysis of the three bands (1,0), (0,0), and (0,1) of the B–X2 system of PbF has been carried out. The bands have been excited in a transformer discharge and photographed in the second order of a 35 ft concave grating spectrograph. The analysis has shown that the bands arise from a 2Σ+–2Π3/2 transition. The rotational constants of the upper and lower states have been determined.


1969 ◽  
Vol 47 (15) ◽  
pp. 1639-1641 ◽  
Author(s):  
O. N. Singh ◽  
M. P. Srivastava ◽  
I. S. Singh

The rotational analysis of the four bands (0,0), (0,1), (0,2), and (1,0) of the A–X1 system of PbF has been carried out. The bands have been excited in a transformer discharge and photographed in the second order of a 35-ft concave grating spectrograph. The analysis has shown that the bands arise from a [Formula: see text] transition. The rotational constants of the upper and lower states have been determined.


1973 ◽  
Vol 51 (2) ◽  
pp. 125-143 ◽  
Author(s):  
R. W. Martin ◽  
A. J. Merer

Rotational analysis of over 50 sub-bands of three emission transitions of 74GeF has given vibrational and rotational constants for the four lowest-lying electronic states of GeF. One of these is a 4Σ− state in Hund's case (a), where all four spin components have been identified. Extensive perturbations between this 4Σ− state and the B2Σ+ state have been analyzed in detail: the two states appear to interact mainly by a second-order mechanism through the so far uncharacterized σπ22Σ+ state, but the surprisingly large J dependence of the perturbation matrix element suggests that another mechanism, possibly involving the ground state, may contribute. Further perturbations, where the lines show an unusual intensity enhancement, appear in those sub-bands with B2Σ+ ν = 4 as upper state.


1987 ◽  
Vol 65 (12) ◽  
pp. 1594-1603 ◽  
Author(s):  
M. Singh ◽  
G. S. Ghodgaonkar ◽  
M. D. Saksena

The A2Π–X2Σ+ system of MgCl has been photographed at high resolution and analyzed for the rotational structure. Analysis of the low-frequency sub-bands of the 0–0, 0–1, and 0–2 bands showed that there is a nonzero Λ doubling in the common vibrational level ν′ = 0, thereby indicating that the A2Π state is regular and not inverted as presumed by earlier workers. Spin-doubling has been seen in the ν = 1 and 2 levels of the X2Σ+ state. Rotational analysis of the high-frequency sub-band has also been done for the 0–0 band.


The absorption spectrum of gaseous hydrogen bromide has been photographed in the region 1180 to 1500 Å, using fourth and fifth orders of a 3 m grating. About forty bands have been observed. The resolving power sufficed for the study of most of the discrete rotational structure. The analysis reveals that few of the bands are related in vibrational progressions and shows rather that they are to be associated with atleast thirty new electronic states.


The spectra of the diatomic hydrides of lithium, sodium and potassium have been studied both in absorption and in emission by several authors, LiH by Nakamura (1930, 1931) and Crawford and Jorgensen (1935), NaH by Hori (1930, 1931) and Olsson (1935), KH by Almy and Hause (1932) and Hori (1933), and recently Almy and Rassweiler (1938) have published details of the absorption spectrum of caesium hydride. All these hydrides show spectra of the “ many-line” type consisting of numerous overlapping bands with open rotational structure and no obvious heads. A rotational analysis shows that they all have the same type of electronic transition, 1Σ → 1Σ ,and are very strongly degraded towards the red. These spectra are all anomalous in that the frequency, ω´ v , and the rotational constant, B'v,increase at first with increasing initial vibrational quantum numbe v `.


1967 ◽  
Vol 45 (8) ◽  
pp. 2805-2807 ◽  
Author(s):  
P. Ramakoteswara Rao ◽  
K. V. S. R. Apparao

The C band system of 63Cu81Br, lying in the region 3 900–4 600 Å, has been photographed in emission under high resolution and rotational analysis of the (2–0), (1–0), (0–0), (0–1), (0–2), and (1–3) bands carried out. The system is shown to involve a 1Σ(C1Σ)–1Σ(X1Σ) transition. The molecular constants of 63Cu81Br obtained from this fine-structure analysis are as follows:[Formula: see text]


1972 ◽  
Vol 50 (13) ◽  
pp. 1579-1586 ◽  
Author(s):  
S. Guha ◽  
S. S. Jois ◽  
R. D. Verma

Four new bands in the red region are observed which have been described in terms of A2Σ+–B2Σ+ and F2Σ+–B2Σ+ systems. A rotational analysis together with deperturbation calculation of one band at 6763 Å has shown that A2Σ+ (ν = 7) and F2Σ+ (ν = 0) vibrational levels are involved in a homogeneous perturbation. The rotational structure study of three bands of a new transition I2Σ+–A2Σ+ has been carried out. From the study of heterogeneous perturbations observed in the I vibrational levels, it has been suggested that the perturbing state is a 2Π state arising from the 3d complex.


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