Table 1. Rotational Parameters for the 2-Naphthalenethiol Dimer and Computational Predictions.

	Experiment		Theory
	Isomer 1	Isomer 2	CC-1	CC-2	CT-1	CT-2	TT-1	CT-3
A/MHza	308.38853(21)e	299.45856(51)	318.10	304.23	294.60	307.2	300.3	390.1
B/MHz	231.75029(16)	246.9652(12)	233.40	250.65	245.68	249.6	242.1	228.2
C/MHz	226.78483(18)	221.5793(15)	231.34	225.72	240.89	225.6	239.4	175.3
DJ/kHz	0.01761(44)	0.1328(56)	0.016	0.012	0.024	0.012	0.022	0.010
DJK/kHz	[0.0]f	–0.242(14)	–0.003	0.028	–0.037	0.032	–0.024	0.005
DK/kHz	0.0234(12)	0.164(10)	0.023	0.005	0.055	0.001	0.044	0.065
d1/kHz	[0.0]	0.0434(28)	–0.002	0.000	–0.007	0.000	–0.009	–0.001
d2/kHz	[0.0]	[0.0]	0.001	–0.001	0.002	–0.001	0.001	–0.001
|μa|/D	-	-	0.0	0.2	1.0	–0.7	0.0	–1.1
|μb|/D	-	++	0.0	0.6	1.1	1.3	0.0	1.2
|μc|/D	+++g	++	1.3	0.6	0.6	1.2	–2.1	0.0
Nb	173	86
σ/kHz	10.6	10.6
ΔEZPE/kJ mol–1c			0.0	0.2	0.5	0.7	0.9	1.1
ΔG/kJ mol–1			1.4	1.8	0.0	0.2	–1.1	1.3
EC/kJ mol–1			–48.7	–47.4	–47.2	–47.2	–46.9	–46.9
ΔESCS-MP2/kJ mol–1d			1.1	0.0	0.4	0.4	1.1	1.3
ΔEDLPNO-CCSD(T)/kJ mol–1			0.7	0.0	0.6	0.8	1.1	2.4

^aRotational constants (A, B, C), centrifugal distortion constants (D_J, D_JK, D_K, d₁, d₂) according to Watson’s S-reduction (I^r-representation) and electric dipole moments (μ_α, α = a, b, c).

^bNumber of measured transitions (N) and standard deviation of the fit (σ).

^cRelative energy with zero-point corrections (ΔE), Gibbs energy (ΔG, 298 K, 1 atm), and complexation energy (ΔE_C including BSSE corrections) using B3LYP-D3(BJ)/def2-TZVP.

^dElectronic energy using SCS-MP2 and DLPNO-CCSD(T), uncorrected for zero-point vibrational energy.

^eStandard errors in parentheses in units of the last digit.

^fParameters in square brackets fixed to zero.

^gThe plus signs denote qualitatively the observation of the corresponding rotational transitions.