The identification of candidate transitions for optically pumped far infrared lasers: Methyl halides and D2O

Two hundred and forty-four candidate transitions for optically pumped far infrared lasers have been identified in C
¹²
H
3
F, C
¹³
H
3
F, C
¹²
D
3
F, C
¹²
H
3
Cl
³⁵
, C
¹²
H
3
Cl
³⁷
, C
¹²
H
3
Br
⁷⁹
, C
¹²
H
3
Br
⁸¹
, and D
2
O using as candidate pump lines, 781 in number, the isotopic forms of CO
2
, the sequence and hot bands of C
¹²
O
2
¹⁶
, and the N
2
O bands. The dominant transition parameters responsible for strong emission from TEA, CW, and long pulse modes of operation were identified by a correlation between known experimental behavior and the pertinent transition parameters, the results being that strong TEA laser emission correlates with ground state population while strong CW and long pulse emission correlate with absorption coefficient. The candidate transitions were subsequently selected on the basis of these parameters using calculated transitions and assignments based on band data from high resolution laser-Stark spectroscopy and measured candidate pump frequencies.