Rotational Analysis of the A–X System of the SiCl Molecule

1971 ◽  
Vol 49 (4) ◽  
pp. 407-411 ◽  
Author(s):  
S. R. Singhal ◽  
R. D. Verma

The A–X system of the SiCl molecule in the region 4500–6400 Å has been excited by an r.f. discharge through a mixture of argon and a trace of SiCl4 vapor, flowing through a quartz tube. Several red degraded and double headed bands with ν′ = 0, 1, 2, and 3 have been observed and the rotational structure of the 0-5, 0-6, 0-7, 0-8, 0-9, 0-10, 1-9, and 1-10 bands has been analyzed. The analysis shows that the bands arise from a 2Σ–2Π transition, 2Π being the ground state of the molecule. The molecular constants have been determined for both the electronic states. The spin coupling constant, Aν, of the X2Π vibrational levels has been found to follow an equation[Formula: see text]

1972 ◽  
Vol 50 (12) ◽  
pp. 1230-1251 ◽  
Author(s):  
D. S. Liu ◽  
W. E. Jones

Three singlet–triplet transitions, b1Σ+−X3Σ−, c1Π–X3Σ−, and d1Π–X3Σ−, and two 3Π–X3Σ− transitions attributed to the molecule AsF, have been found in the regions 1900–2300 Å and 7000–7400 Å. The vibrational analysis for the observed systems and the rotational analysis of the singlet–triplet transitions are complete. The analysis shows that the ground state X3Σ− belongs to Hund's case c with a spin coupling constant λ of about 70 cm−1. The analysis of the observed transitions and a discussion of the relative position and molecular configurations of the observed states are presented.


1975 ◽  
Vol 53 (4) ◽  
pp. 411-419 ◽  
Author(s):  
R. D. Verma ◽  
S. R. Singhal

An extensive study of the β system of the PO molecule has been carried out. The rotational analysis of 23 bands has yielded the constants of the ν = 0–9 levels of the B2Σ+ state and of the ν = 0–11 levels of the X2Π state with a precision higher than previous measurements. The spin coupling constant, Aν, evaluated for the 12 levels of X2Π is found to follow the equation Aν = 224.03 + 0.18ν–0.013ν2. The perturbations observed in the B2Σ (ν = 6 and 7) levels have been interpreted as being caused by a 4Σ− state and the B′2Π state. A deperturbation calculation has been carried out to evaluate the molecular constants of the PO molecule in the 4Σ− state. Several new bands were also observed; some of these belong to the β and B′–X systems and others are left unassigned.


1972 ◽  
Vol 50 (19) ◽  
pp. 2265-2276 ◽  
Author(s):  
J. M. Berthou ◽  
B. Pascat ◽  
H. Guenebaut ◽  
D. A. Ramsay

Rotational analyses have been carried out for the 0ν′20–000 bands of the [Formula: see text] electronic transition of PH2 with ν′2 = 1–8. Approximately 1000 lines have been assigned. The earlier analysis of the 000–000 band has been extended and improved molecular constants obtained. The Hamiltonian used for this band does not fit the excited state levels with [Formula: see text]. Term values are therefore given for all observed levels. Empirical formulas are presented which give approximate fits to the higher levels. Numerous rotational perturbations are found in the excited state. Perturbations up to 0.6 cm−1 are also found in the 000 level of the excited state. These latter perturbations can only be caused by the higher vibrational levels of the ground state.


1978 ◽  
Vol 56 (5) ◽  
pp. 587-600 ◽  
Author(s):  
D. Gauyacq ◽  
M. Horani

A new emission spectrum in the red region (6000–8000 Å) has been recorded from a low pressure hot cathode discharge through carbon disulfide. This band system has been assigned to the A2Πi–X2Σ+ transition of the CS+ molecular ion on the basis of the rotational analysis and comparison with other nine valence-electron molecules. Molecular constants have been obtained by direct least squares fits of the line frequencies to the difference of the eigenvalues of standard 2Π and 2Σ+ matrices.A local perturbation in the A2Πi (ν = 5) state has been studied quantitatively. The position of the perturbing vibrational level in the X2Σ+ state has been determined within a few centimetre−1. This study gave a consistent set of molecular constants for the ground state of CS+ and allowed a partial deperturbation treatment of the observed vibrational levels of the excited A2Πi state.Numerous bands are also observed in the 4000 Å region. A discussion is given concerning the possible assignment of bands at 4059 and 4110 Å to the CS+B2Σ+–A2Πi (0,0) transition.


The absorption spectrum of AgF in the region 300.0 to 355.0 nm consists of a continuum centred at about 303.0 nm and two-band systems, A0 + , and B0 + ← X 1 Ʃ + . Rotational analyses have been made for all seven bands observed in the A─X system and of four bands in the B─X system, for both 107 AgF and 109 AgF. State A seems to have a very low dissociation energy and may possess only two stable vibrational levels. Lines at high J appear diffuse, indi­cating predissociation, perhaps by rotation. State B is also predissociated and only the bands with v ' ═ 0 show sharp rotational structure. The predissociating state is probably an Ω ═ 1 state which is the upper state of the 303.0 nm continuum. Constants for the ground state of 107 AgF are as follows: G v ═ 513.447 ± 0.009 ( v + ½) ─ 2.593 ± 0.002 ( v + ½) 2 B v ═ 0.26567 ─ 0.001901± 8 ( v + ½).


1971 ◽  
Vol 49 (15) ◽  
pp. 2033-2051 ◽  
Author(s):  
L. Harding ◽  
W. E. Jones ◽  
K. K. Yee ◽  
A. Jenouvrier ◽  
D. Daumont ◽  
...  

The vibrational and rotational analysis of 12 red degraded bands of N80Se, in the region 2800 to 3200 Å, is reported. These bands are attributed to two progressions, ν′ = 1 and ν′ = 2, of the subsystem C2Δ5/2–X2Π3/2 and to two progressions, ν′ = 0, of the system B2Σ–X2Π(a).Tables of molecular constants of the observed states are given. For the first time it has been possible to calculate the spin–orbit coupling constant, Aeff, of the ground state, X2Π(a).


1980 ◽  
Vol 33 (6) ◽  
pp. 1231 ◽  
Author(s):  
KR Morgan ◽  
NF Curtis

Singlet ground state compounds of nickel(II) with tetradentate β-imino amine ligands are formed by reaction of complexes of ethane-1,2- diamine, propane-1,2-diamine, 3-azapentane-1,5-diamine, 4-azaheptane- 1,7-diamine and (2-aminoethyl)piperazine with 4-amino-4-methylpentan-2- one, amp. With 3,6-diazaoctane-1,8-diamine, a compound with a pentadentate β-imino ligand is formed, water completing octahedral coordination, and with 2-aminoethanol a bis compound of a tridentate β-imino amine alcohol ligand is formed. More complex products are formed by the hydrazone and oxime of amp. The oxime compound shows appreciable antiferromagnetism, with the spin-coupling constant, J, about -70 cm-1, determined from magnetic susceptibility measurements over 100-300 K.


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.


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.


1996 ◽  
Vol 74 (8) ◽  
pp. 1524-1525 ◽  
Author(s):  
Ted Schaefer ◽  
Guy M. Bernard ◽  
Frank E. Hruska

An excellent linear correlation (r = 0.9999) exists between the spin–spin coupling constants 1J(1H,13C), in benzene dissolved in four solvents (R. Laatikainen et al. J. Am. Chem. Soc. 117, 11006 (1995)) and Ando's solvation dielectric function, ε/(ε – 1). The solvents are cyclohexane, carbon disulfide, pyridine, and acetone. 1J(1H,13C)for gaseous benzene is predicted to be 156.99(2) Hz at 300 K. Key words: spin–spin coupling constants, 1J(1H,13C) for benzene in the vapor phase; spin–spin coupling constants, solvent dielectric constant dependence of 1J(1H,13C) in benzene; benzene, estimate of 1J(1H,13C) in the vapor; nuclear magnetic resonance, estimate of 1J(1H,13C) in gaseous benzene.


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