The D and D′ states of the PO molecule

Abstract

A rotational analysis of the 0–0, 0–1, and 0–2 bands of the D–B and D′–B systems of PO in the region 5500–6900 Å has been carried out from a spectrum obtained at a resolution higher than that of previous workers (Couet and Guenebaut 1966; Couet et al. 1967). The mutual perturbation between D2Πr and D′2Πr has been confirmed from the rotational analysis of the 0–0 and 0–1 bands of the D–A and D′–X systems in the region 2000–2200 Å. The analysis of the D′–X bands has shown that the previously reported E′ state lying between the D and D′ states is actually part of the D′ state. The constants of the D2Πr, D′ 2Πr, B2Σ+, and X2Π states are evaluated and compared with the constants of earlier workers to remove the inconsistency existing in their values for the B and X states.The isotopic bands corresponding to P18O of the D–B and D′–B systems are obtained, thus showing that the D′ state has an anomalous isotopic shift and that the observed levels of the D and D′ states have the vibrational quantum number ν =.

Emission spectrum of the PO molecule. I. A new B′2Πi–X2Πr transition

“…These constants give AGlI2 = 1220.18 cm-I in exact agreement with the value recently established by Verma and Dixit (1968). The vibrational constants of X211 established from the present work are in agreement with those given by Rao from a rotational analysis of they bands.…”

“…Experimental conditions and the spectrograph used in photographing the spectrum were the same as described recently by Verma and Dixit (1968). The new spectrum was excited by an r.f.…”

“…At the time this work was undertaken, the five excited states of the PO molecule, namely A2Cf, B2Cf, C1'C-, D 2 n r , and D'211r had been established by rotational analyses of the bands involving these states (Rao 1958;Singh 1959;Guenebaut et al 1966 ;Narasimham et al 1965 ;Verma and Dixit 1968;Couet et al 1968). Recently, two more states, C and E, reported earlier (Dressler 1955), have been found to be *C-and 'A, respectively (Dixit and Verma 1970).…”

Spectral study of the phosphorus glow

“…glow are B' 211i-X 'I1, (Verma 1970), C' 2Z-X 211r (Narasimham et al 1965 ;Guenebaut et al 1966), C-X211, (Dressler 1955), and D 211,-X211, (Dressler 1955 ;Verma and Dixit 1968). Bands belonging to the B1-X transition are superimposed on the continuum in the region 3800-4500 A. Wavelengths (A) and assignments of the new B'-X bands are 4444.7 (0-9), 4345.6 (1-9), 4300.5 (1-9), 4208.4 (2-9), and 4167.2 (2-9).…”

Emission Spectrum of the PO Molecule. Part II.2Σ–2Σ Transitions

“…In a recent paper (Verma and Dixit 1968) it was shown that the rotational structure of the D' state breaks off at 49 536 cm-' above X211 (To = 0). No other level of D and D', above 49 536 cm-' has been observed.…”