Table 2. Derived spectroscopic parameters (in MHz) for CH₃CO⁺.

Constant	Spacea	Laboratoryb	Mergedc
B	9134.47424(82)	9134.47083(27)	9134.47211(20)
DJ	4.014(12) 10−3	3.99198(25) 10−3	3.99307(21) 10−3
DJK	1.8847(53)10−1	1.87616(41) 10−1	1.87736(46) 10−1
HJK		8.66(33) 10−7	9.56(37) 10−7
HKJ		6.58(59) 10−6	7.19(74) 10−6
rms(kHz)d	6.9	34.3	33.2
Jmin/Jmax	1/7	10/27	1 /27
Kmin/Kmax	0/1	0/6	0/6
$N_{lines}^e$	10	79	89
νmax(GHz)	127.87	492.95	492.95

Notes.

^aFit to the lines of CH₃CO⁺ observed in TMC-1. In this fit, the J=7-6 and K=0,1 lines observed in L1527 (with frequencies of 127877.133±0.025 and 127874.494±0.050 MHz, respectively) have been included (see Fig. A.1 and Appendix A).

^bFit to the lines of CH₃CO⁺ observed in the laboratory.

^cFit to the the lines of CH₃CO⁺ observed in space and in the laboratory.

^dThe standard deviation of the fit (in kHz). ^(e) Number of lines included in the fit.