Table 1.

Spectroscopic parameters^a of HSO.

Parameter	This work		Endo et al. (1981)b
	Experimentc	Theoryd
A0 / MHz	299483.90(12)	300316.2	299484.68(14)
B0 / MHz	20502.7847(10)	20527.6	20502.7823(83)
C0 / MHz	19135.6989(10)	19160.0	19135.7168(83)
DN / kHz	29.4675(13)	28.61	29.64(11)
DNK / kHz	904.18(11)	882.33	903.41(40)
DK / MHz	26.24(11)	25.99	[27.2]
d1 / kHz	-2.02504(43)	-1.86	-1.926(65)
d2 / kHz	-0.35187(30)	-0.29	-0.527(52)
HN / mHz	-28.42(75)	-29.07
HNK / Hz	2.779(88)	2.28
HKN / Hz	144.7(43)	126.26
HK / kHz	[6.43]	6.43
h1 ×102 / mHz	[-8.32]	-8.32
h2 / mHz	[3.69]	3.69
h3 / mHz	1.10(22)	0.725
LJK / mHz	-11.4(32)
∈aa / MHz	-10366.15(10)	-10979.0(-10940.5)	-10366.17(16)
∈bb / MHz	-426.633(17)	-439.4(-438.9)	-426.683(31)
∈cc / MHz	0.191(21)	2.82(3.29)	0.210(48)
${\tilde{\in }}_{ab}/\text{MHz}$	377.971(16)	404.8(403.3)	377.81(80)
${\in }_{\mathrm{aa}}^{NK}$e / MHz			0.047(12)
${\in }_{\mathrm{aa}}^{NK}$e / MHz	2.979(10)		3.023(35)
${\in }_{\mathrm{bb}}^{NK}$e / MHz	-0.001676(32)
${\in }_{\mathrm{bb}}^{NK}$e / MHz	0.0638(36)
${\in }_{\mathrm{cc}}^{NK}$e / MHz	-0.114(30)
aF(H) / MHz	-35.72(50)	-35.94(-34.58)	-35.98(42)
Taa(H) / MHz	-11.932(86)	-12.38(-13.25)	-11.883(71)
Tbb(H) / MHz	10.45(14)	10.71(11.25)	10.41(11)
Tab(H) / MHz	[-7.53] f	-7.56(-7.53)	[-7.8] f
Caa(H) / kHz		-20.18(-21.56)
Cbb(H) / kHz		2.51(2.51)
Ccc(H) / kHz		-1.52(-1.59)

^aWatson S -reduction. Uncertainties (1σ) are in units of the last significant digit.

^bWatson S -reduction parameters obtained by re-fitting the frequency values reported in (Endo et al. 1981).

^cValues given in square brackets are kept fixed at the computed values.

^dEquilibrium rotational constants at the CBS+CV+fT+fQ level augmented by vibrational corrections at the CCSD(T)/cc-pCVQZ level. Quartic and sextic centrifugal-distortion constants at the CCSD(T)/cc-pCVQZ level. Hyperfine parameters - equilibrium values (given in parentheses): electronic and nuclear SR constants at the CCSD(T)/cc-pCV5Z level, isotropic and anisotropic hyperfine coupling constants at the aug-cc-pCV5Z level. Equilibrium values augmented by vibrational corrections at the CCSD(T)/cc-pVTZ level.

^eCentrifugal-distortion dependence of the electron spin-rotation constants, as given in (Endo et al. 1981).

^fThe negative sign means the sign of T_ab is opposite to that of 1/2(∈ab + ∈ba).