Table 15.

Comparison of computed and experimental harmonic (H) and anharmonic (A) ZPVE (in KJ mol⁻¹) and absolute entropies at 298.15 K and 1 atm (in J mol⁻¹ K⁻¹), for linear and symmetric top molecules

	MP2[a]		B3LYP[b]		B2PLYP[a]		Best theo.	Expt.
	H	A	H	A	H	A
HCN
ZPVE	41.42	41.05	42.46	42.02	42.31	41.90	[c]	41.61[c]
Δ		−0.37		−0.44		−0.41
S	201.79	201.82	201.99	202.20	201.39	201.50	—	201.83[d,g]
CO2
ZPVE	30.18	30.08	30.49	30.36	30.24	30.12	[e]	—
Δ		−0.10		−0.13		−0.12
S	213.88	213.95	213.74	213.78	213.72	213.79	—	213.69[d,g]
C2H2
ZPVE	69.65	68.93	70.73	69.58	70.59	69.85	[e]	—
Δ		−0.72		−1.15		−0.74
S	200.82	200.92	200.08	201.14	200.06	200.34	—	200.85[d,g]
PH3
ZPVE	64.39	63.59	62.21	61.37	63.49	62.67	[f]	—
Δ		−0.80		−0.84		−0.82
S	209.90	209.98	210.25	210.33	209.97	210.05	—	210.13[d,g]
ClCH3
ZPVE	100.75	99.36	98.73	97.34	99.79	98.43	—	—
Δ		−1.39		−1.39		−1.36
S	233.77	233.92	234.42	234.58	234.06	234.22	—	234.26[d,g]
FCH3
ZPVE	104.80	103.37	102.61	101.18	103.72	102.30	—	—
Δ		−1.43		−1.43		−1.42
S	222.52	222.62	222.75	222.85	222.59	222.69	—	222.73[d,g]

Δ's are the anharmonic corrections.

Basis sets: [a] AVTZ, [b] SNSD.

Refs.: [c]¹⁵⁶; [d]²⁰⁴; [e]¹⁵⁵; [f]⁵⁵.

[g] The tabulated values have been lowered by 0.11 J mol⁻¹ K⁻¹, to pass from the original 1 MPa values to 1 MPa (see “reference part” in [204]).