Table 4.

Fundamentals (in cm${}^{-1}$) and calculated force constants (in aJ Å${}^{-2}$) for certain pyramidal molecules. References from which the fundamental energies were taken are indicated.

Molecule	${\mathit{\nu }}_1$	${\mathit{\nu }}_2$	${\mathit{\nu }}_3$	${\mathit{\nu }}_4$	${\mathit{f}}_{\mathit{rr}}^{\left(\mathit{N}\right)}$	${\mathit{f}}_{{\mathit{rr}}^{\prime }}^{\left(\mathit{N}\right)}$	${\mathit{f}}_{\mathit{\theta }\mathit{\theta }}^{\left(\mathit{N}\right)}$	${\mathit{f}}_{\mathit{\theta }{\mathit{\theta }}^{\prime }}^{\left(\mathit{N}\right)}$
${}^{14}$NH${}_3$ [62]	3336.08	932.43	3443.68	1626.28	6.3871	−0.0117	0.5252	−0.0815
${}^{14}$NT${}_3$ [63]	2014.1	656.37	2184.76	996.28	6.5989	−0.0138	0.5402	−0.0645
${}^{15}$NCl${}_3$ [64]	541.7	364.8	632.3	262.8	2.4275	0.3837	0.2321	0.0571
${}^{14}$NCl${}_3$ [64]	554.2	365.2	644	263	2.4189	0.4073	0.2202	0.0533
${}^{31}$PH${}_3$ [65]	2321.12	992.13	2326.87	1118.31	3.0853	0.0006	0.3303	−0.0203
PCl${}_3$ [66]	515	258.3	504	186	2.5695	0.3104	0.1963	0.0222
PBr${}_3$ [66]	390	159.9	384.4	112.8	2.0586	0.3502	0.0959	0.0072
${}^{75}$AsH${}_3$ [67]	2115.16	906.75	2126.42	999.23	2.6198	−0.0080	0.2727	−0.0139
AsF${}_3$ [68]	740	338	703	263	4.5824	0.2579	0.3644	0.0489
AsCl${}_3$ [66]	416.5	192.5	319	150.2	2.2860	0.2180	0.1829	0.0211
AsBr${}_3$ [66]	272	128	287	99	1.8326	0.1105	0.1236	0.0079
${}^{121}$SbH${}_3$ [69]	1890.50	782.25	1894.50	827.86	2.0944	−0.0025	0.1929	−0.0053
SbF${}_3$ [70]	666	250	634	213	4.0305	0.1828	0.2436	0.0223
SbCl${}_3$ [66]	380.7	150.8	358.9	121.8	2.1794	0.1529	0.1364	0.0156
BiH${}_3$ [71]	1733.25	726.7	1734.47	751.24	1.7632	−0.0008	0.1619	−0.0035
BiCl${}_3$ [66]	342	123	322	107	1.9351	0.1179	0.1112	0.0116
BiBr${}_3$ [66]	220	77	214	63	1.5975	0.0998	0.0750	0.0076
BiI${}_3$ [66]	162	59.7	163.5	47	1.2453	0.0747	0.0575	0.0056