NOTE: Reanalysis was carried out with new unpublished millimeter measurements by F.J. Lovas and R.D. Suenram. The analysis is discussed in Appendix 2 and the new measurements are listed in Table A.2.2.

Watson's Determinable Parameters	Present Analysis a [MHz]	Derived Parameters (assuming planarity conditions)
A	58 782.6832(151)	A	58 782.655(15)
B	10 896.3521(30)	B	10 896.418(3)
C	9 167.373 74(255)	C	9 167.422(3)
1	0.174 809(1681)	bbcc	-0.055 68(9)
2	-0.011 7994(2618)	ccaa	0.1329(5)
3 b	2.590(5)	aabb	0.0976(12)
aaaa	-6.651 478(1426)	aabb (1)	0.4165(7)
bbbb	-0.092 781 32(10292)	aabb (2)	0.4044(6)
cccc	-0.036 7054(701)	aabb (3)	0.4044(6)
HJ	(0.591 37 ± 0.22) x 10-7	abab (1)	-0.158 95(27)
HJK	(0.4706 ± 0.38) x 10-6	abab (2)	-0.148 45(41)
HKJ	-0.222 90(836) x 10-4	abab (3)	-0.146 83(44)
HK	0.176 68(978) x 10-3		-0.355(11) x 10-3
hJ c	0.2282(461) x 10-7
hJK	0.1664(665) x 10-5
hK	(0.565 ± 17.2) x 10-6
Std. dev.	0.066
No. lines fit	108

^a The uncertainties quoted are one standard deviation as estimated by the least-squares fit. The number of significant figures quoted are necessary to reproduce the calculated transition frequencies within their standard deviation.

^b Strictly speaking, ₃ is not a determinable parameter, but is calculated from ₁, ₂, _aaaa, and _bbbb using the planarity conditions.

^c Watson uses 2h_J for this parameter.

 

Rotational Constants for the Excited Vibrational States of F₂O.

Vib. State 1 2 3	A [MHz]	B [MHz]	C [MHz]	Ref.
1  0  0	59 213.58(100)	10 824.35(50)	9 128.09(50)	66019
1  0  0 a	58 744.08(100)	10 830.66(50)	9 160.23(50)
0  1  0	59 481.65(100)	10 854.07(50)	9 114.13(50)
0  2  0	59 711.17(100)	10 818.01(50)	9 092.99(50)
0  0  1	58 197.62(100)	10 826.87(50)	9 052.16(50)

^a Corrected for the effect of ₁ - 2₂ Fermi resonance.

Zeeman Constants, Spin-Rotation Constants Electric Dipole Moment of F₂O.

Parameter	Value	Ref.
Zeeman constants:
gaa (µN)	-0.213(5)	[69027]
gbb (µN)	-0.058(2)
gcc (µN)	-0.068(2)
2aa - bb - cc a	-8.8(14)
2 bb - aa - cc a	-4.4(7)
Spin-rotation constants:
Maa (kHz)	-42(1)	[65011]
Mbb (kHz)	-22(1)
Mcc (kHz)	-49(1)
Electric dipole moment:
µb [C · m]      µb [D]	0.991(17) x 10-30       0.297(5)	[61008]

^a These are magnetic susceptibility constants.