Vibrational Deactivation of Excited States of Nitrogen created in a Microwave Discharge

Optical transitions from two microwave discharge excited states of argon have been observed using cavity ring-down spectroscopy. These transitions originate on the high-lying levels, 3d[1/2] 1° and 3d[3/2] 2° , and terminate on the nf ′[5/2] Rydberg (n = 8 to 22) levels, which, except for n = 8, lie between the 2P3/2 and 2P1/2 ionization thresholds. In total, 24 such spectral lines have been observed. The quantum defect for the f ′ series has been measured and is compared to previously measured values. We observe a nearly threefold jump in line width in going from n = 8 to n = 9, below and above the 2P3/2 threshold, respectively. The line widths are broad and increase monotonically with n (above 9), in contrast to the narrowing of line widths usually observed. We cannot attribute this to a single source but conclude that collisional, quasielastic l-mixing of the nf ′[5/2] Rydberg states plays a significant role.

Download Full-text

High temperature studies of singlet excited oxygen, O 2 ( 1 Σ g + ) and O 2 ( 1 Δ g ), with a combined discharge flow/shock tube method

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1979.0095 ◽

1979 ◽

Vol 367 (1730) ◽

pp. 395-410 ◽

Cited By ~ 24

Keyword(s):

Steady State ◽

Shock Tube ◽

Excited States ◽

High Temperatures ◽

Rate Constants ◽

Microwave Discharge ◽

Discharge Flow ◽

Direct Collision ◽

State Concentration ◽

Excited Oxygen

The excited states of oxygen, O 2 ( 1 Δ g ) and O 2 ( 1 Σ g + ), generated in a microwave discharge, were shock heated in order to study their reactions at temperatures in the range 650-1650 K. The increase in the dimol emission (634 nm) from O 2 ( 1 Δ g ) behind the shock front is consistent with the simple collisional model for the production of the emission; the rate of quenching of O 2 ( 1 Δ g ) by O 2 is too slow to measure at high temperatures with the technique. The emission from O 2 ( 1 Σ g + ) increases because of the shock compression and then is further enhanced by a displacement in the steady state concentration which is maintained by the two reactions pooling: 2O 2 ( 1 Δ g )->O 2 ( 1 Σ g + )+O 2 ( 3 Σ g - ) k p ; quenching: O 2 ( 1 Σ g + )+M->O 2 ( 3 Σ g - or 1 Δ g )+M; k q M . The relaxation to the enhanced level of emission permits k M q to be measured directly and then k p is calculated from the enhanced steady state emission level and k M q . There is no evidence for direct, collision induced! enhancement of the emission from O 2 ( 1 Σ g + ). Curved Arrhenius plots of the rate constants were found; some values are given in table 2. The results appear to indicate that in each case there are two mechanisms operating; one involving short range forces, and the other, long range forces or a collision complex. An evaluation is given of the discharge flow-shock tube technique as a method for determining rate constants at high temperatures.

Download Full-text

Nonequilibrium characteristics in the rotational temperature of CO excited states in microwave discharge CO2 plasma

Japanese Journal of Applied Physics ◽

10.35848/1347-4065/abee04 ◽

2021 ◽

Vol 60 (4) ◽

pp. 046005

Author(s):

Shota Yamada ◽

Yuki Morita ◽

Atsushi Nezu ◽

Hiroshi Akatsuka

Keyword(s):

Excited States ◽

Microwave Discharge ◽

Rotational Temperature ◽

Co2 Plasma

Download Full-text

Vuv Spectra Y to Mo

International Astronomical Union Colloquium ◽

10.1017/s0252921100107808 ◽

1988 ◽

Vol 102 ◽

pp. 239

Author(s):

M.S.Z. Chaghtai

Keyword(s):

Excited States ◽

Spectral Analyses ◽

Vuv Spectra

Using R.D. Cowan’s computations (1979) and parametric calculations of Meinders et al (1982), old analyses are thoroughly revised and extended at Aligarh, of Zr III by Khan et al (1981), of Nb IV by Shujauddin et Chaghtai (1985), of Mo V by Tauheed at al (1985). Cabeza et al (1986) confirmed the last one largely.Extensive studies have been reported of the 1–e spectra, Zr IV (Rahimullah et al 1980; Acquista and Reader 1980), Nb V (Shujauddin et al 1982; Kagan et al 1981) and Mo VI (Edlén et al 1985). Some interacting 4p54d2levels of these spectra have been reported from our laboratory, also.Detailed spectral analyses of transitions between excited states have furnished complete energy values for J ≠ 1 levels of these spectra during 1970s and 80s. Shujauddin et al (1982) have worked out Nb VI and Tauheed et al (1984) Mo VII from our lab, while Khan et al (1981) share the work on Zr V with Reader and Acquista (1979).

Download Full-text