Dimroth and Reichardt ET

Dimroth and Reichardt determined the wavenumber of the absorption maximum for a betain dye as a measure of the ionizing power of solvents. It is converted to kcal/mol (2.86x104λ-1) to give ET.
Normalizing to a scale from TMS (0) to water (1) gives ETN.
See e.g. IUPAC Gold Book.

NameFormulaETETN
1,1,1,3,3,3-hexafluoro-2-propanolC3H2F6O65.31.07
1,1,1-trichloroethaneC2H3Cl336.20.17
1,1,2,2-tetrachloroethaneC2H2Cl439.40.27
1,1,3,3-tetramethylguanidineC5H13N339.30.27
1,1-dichloroethaneC2H4Cl239.40.27
1,2,3-propanetriolC3H8O357.00.81
1,2-diaminoethaneC2H8N242.00.35
1,2-dibromoethaneC2H4Br238.30.23
1,2-dichlorobenzeneC6H4Cl238.00.23
1,2-dichloroethaneC2H4Cl241.30.33
1,2-dimethoxyethaneC4H10O238.20.23
1,3,3-trimethyl-2-oxabicyclo[2.2.2]octaneC10H18O34.00.10
1,3,5-trimethylbenzeneC9H1232.90.07
1,3-dichlorobenzeneC6H4Cl236.70.19
1,3-dimethylbenzeneC8H1033.30.08
1,3-dioxolan-2-oneC3H4O348.60.55
1,3-dioxolaneC3H6O243.10.38
1,4-difluorobenzeneC6H4F236.40.18
1,4-dimethylbenzeneC8H1033.10.07
1-bromobutaneC4H9Br36.60.18
1-chlorobutaneC4H9Cl36.90.19
1-iodobutaneC4H9I34.90.13
2,2,2-trifluoroethanolC2H3F3O59.80.90
2,6-dimethylpyridineC7H9N36.90.19
2-bromopyridineC5H4BrN41.30.33
2-butanolC4H10O47.10.51
2-butanoneC4H8O41.30.33
2-chloroanilineC6H6ClN45.50.46
2-chloroethanolC2H5ClO55.50.77
2-cyanopyridineC6H4N244.20.42
2-fluoropyridineC5H4FN42.40.36
2-heptanoneC7H14O41.10.32
2-methyl-1-propanolC4H10O48.60.55
2-methyl-2-butanolC5H12O41.10.32
2-methyl-2-propanolC4H10O43.70.40
2-methyltetrahydrofuranC5H10O36.50.18
2-pentanoneC5H10O41.10.32
2-phenylacetonitrileC8H7N42.70.37
2-phenylethanolC8H10O49.50.58
2-propanolC3H8O49.20.57
2-propanoneC3H6O42.20.35
2-propen-1-olC3H6O52.10.66
2-pyrrolidoneC4H7NO48.30.54
3,4-dimethylpyridineC7H9N38.90.25
3-bromopyridineC5H4BrN39.70.28
3-chlorophenolC6H5ClO60.80.93
3-methyl-1-butanolC5H12O49.00.56
3-methylphenolC7H8O52.80.68
3-pentanoneC5H10O39.30.27
3-phenylpropanolC9H12O48.50.55
4-methyl-2-oxo-1,3-dioxolaneC4H6O346.60.49
4-methyl-2-pentanoneC6H12O39.40.27
4-methylphenolC7H8O53.30.70
4-methylpyridineC6H7N39.60.27
acetic acidC2H4O255.20.76
acetic anhydrideC4H6O343.90.41
acetonitrileC2H3N45.60.46
acetophenoneC8H8O40.60.31
anilineC6H7N44.30.42
benzeneC6H634.30.11
benzonitrileC7H5N41.50.33
benzyl alcoholC7H8O50.40.61
bis(2-methoxyethyl) etherC6H14O338.60.24
bis-(2-chloroethyl) etherC4H8Cl2O41.60.34
bromobenzeneC6H5Br36.60.18
butanenitrileC4H7N43.10.38
butanoic acidC4H8O254.40.73
butanolC4H10O50.20.60
butyl acetateC6H12O238.50.24
butylamineC4H11N37.60.21
carbon disulfideCS232.80.06
chloroacetonitrileC2H2ClN46.40.48
chlorobenzeneC6H5Cl36.80.19
cis-decalinC10H1831.20.02
cyclohexaneC6H1230.90.01
cyclohexanolC6H12O46.90.50
cyclohexanoneC6H10O39.80.28
cyclopentanoneC5H8O39.40.27
decaneC10H2231.00.01
decanolC10H22O47.70.52
di-n-butyl sulfideC8H18S34.90.13
dibenzyl etherC14H14O36.30.17
dibromomethaneCH2Br239.40.27
dibutyl etherC8H18O33.00.07
dichloromethaneCH2Cl240.70.31
diethyl carbonateC5H10O337.00.19
diethyl etherC4H10O34.50.12
diethyl sulfideC4H10S35.70.15
diethylamineC4H11N35.40.15
diiodomethaneCH2I236.50.18
diisopropyl etherC6H14O34.00.10
diisopropyl sulfideC6H14S34.90.13
dimethyl carbonateC3H6O338.80.25
dimethyl phthalateC10H10O440.70.31
dimethyl sulfideC2H6S26.8-0.12
dimethyl sulfoxideC2H6OS45.10.44
dimethylcyanamideC3H6N243.80.40
dioxaneC4H8O236.00.16
diphenyl etherC12H10O35.50.15
dipropyl etherC6H14O34.00.10
dodecaneC12H2631.10.01
ethanediolC2H6O256.30.79
ethanolC2H6O51.90.65
ethoxybenzeneC8H10O36.60.18
ethyl acetateC4H8O238.10.23
ethyl benzoateC9H10O238.10.23
ethyl chloroacetateC4H7ClO239.40.27
ethyl formateC3H6O240.90.31
ethyl trichloroacetateC4H5Cl3O238.70.25
fluorobenzeneC6H5F37.00.19
formamideCH3NO56.60.80
formic acidCH2O257.70.83
furanC4H4O36.00.16
heptaneC7H1631.10.01
heptanoic acidC7H14O255.00.75
hexafluorobenzeneC6F634.20.11
hexamethylphosphoramideC6H18N3OP40.90.31
hexaneC6H1431.00.01
hexanoic acidC6H12O255.40.76
hexanolC6H14O48.80.56
iodobenzeneC6H5I36.20.17
methanolCH4O55.40.76
methoxybenzeneC7H8O37.10.20
methyl acetateC3H6O240.00.29
methyl benzoateC8H8O238.10.23
methyl formateC2H4O245.00.44
methyl propanoateC4H8O238.00.23
methylbutaneC5H1230.90.01
morpholineC4H9NO41.00.32
N,N,N',N'-tetramethylureaC5H12N2O41.00.32
N,N-diethylacetamideC6H13NO42.40.36
N,N-diethylformamideC5H11NO41.80.34
N,N-dimethylacetamideC4H9NO43.70.40
N,N-dimethylanilineC8H11N36.50.18
N,N-dimethylcyclohexylamineC8H17N37.30.20
N,N-dimethylformamideC3H7NO43.80.40
N-methylacetamideC3H7NO52.00.66
N-methylanilineC7H9N42.50.36
N-methylcaprolactameC7H13NO41.60.34
N-methylformamideC2H5NO54.10.72
N-methylpyrrolidonC5H9NO42.20.35
nitrobenzeneC6H5NO241.20.32
nitromethaneCH3NO246.30.48
octaneC8H1831.10.01
octanolC8H18O48.30.54
oxaneC5H10O36.60.18
oxolan-2-oneC4H6O244.30.42
pentafluoropyridineC5F5N36.30.17
pentaneC5H1231.10.01
pentanoic acidC5H10O255.30.76
pentanolC5H12O49.10.57
phenolC6H6O53.40.70
piperidineC5H11N35.50.15
propanenitrileC3H5N43.60.40
propanoic acidC3H6O255.00.75
propanolC3H8O50.70.62
propyl acetateC5H10O237.50.21
pyridineC5H5N40.50.30
pyrrolidineC4H9N39.10.26
quinolineC9H7N39.40.27
sulfolaneC4H8O2S44.00.41
tetrachloroetheneC2Cl431.90.04
tetrachloromethaneCCl432.40.05
tetrahydrofuranC4H8O37.40.21
tetramethylsilaneC4H12Si30.70.00
thianeC5H10S35.90.16
thiolaneC4H8S36.70.19
thiolane-1-oxideC4H8OS43.60.40
tolueneC7H833.90.10
trans-1,2-dichloroetheneC2H2Cl241.90.35
tribromomethaneCHBr337.70.22
tributyl phosphateC12H27O4P39.60.27
tributylamineC12H27N32.10.04
trichloroetheneC2HCl335.90.16
trichloromethaneCHCl339.10.26
triethyl phosphateC6H15O4P41.70.34
triethylamineC6H15N32.10.04
trimethyl phosphateC3H9O4P43.60.40
vinyl benzeneC8H834.80.13
waterH2O63.11.00