Optical constants

Refractive index of C₇H₁₆ (Heptane)

Kerl and Varchmin 1995: n-Heptane; 293 K; n 0.326–0.644 µm

Data: formula 5
Range: 0.326–0.644 µm
Temperature: 293 K
Licence: CC0-1.0

Axis Log x Log y

Click the plot to set the calculator wavelength.

At one wavelength

Refractive index n: 1.38887
Extinction coefficient k: 0

Permittivity ε₁: 1.92895
Permittivity ε₂: 0

Absorption coefficient α: 0 cm⁻¹
Penetration depth δ = λ/(2πk): — nm

Abbe number V_d: —
Chromatic dispersion dn/dλ: -0.0334512 µm⁻¹

Group index n_g: 1.40852
Group velocity dispersion: 68.5371 fs²/mm

Dispersion parameter D: -373.906 ps/(nm·km)
Photon energy: 2.11001 eV

ε = (n + ik)², α = 4πk/λ, n_g = n − λ dn/dλ, GVD = λ³/(2πc²) d²n/dλ², D = −(λ/c) d²n/dλ². Group-velocity dispersion is given for formula data only.

Use it in Lightsmith

Load this data in Python, simulate in one more line

pip install lightsmith

import lightsmith as ls

# C7H16 (Heptane): Kerl and Varchmin 1995: n-Heptane; 293 K; n 0.326–0.644 µm
c7h16 = ls.fetch_refractiveindex("organic", "heptane", "Kerl-293K", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(c7h16.range_nm)  # (326, 644) nm
eps = c7h16.eps([633])  # complex permittivity

Downloads the original record once (pinned to the imported snapshot) and caches it.

import json, urllib.request
import lightsmith as ls

url = "https://materials.lightsmith.dev/v1/datasets/ds_4e01682d9aca/lightsmith"
c7h16 = ls.Tabulated.model_validate(json.load(urllib.request.urlopen(url)))
print(c7h16.source)  # citation and provenance travel with the data

Any dataset here, as the library's Tabulated material (heptane/kerl-varchmin-1995-293k).

# ... load c7h16 as above, then:
sim = ls.Simulation(
    particles=[ls.Particle(shape=ls.Sphere(radius_nm=50), material=c7h16)],
    medium_index=1.0,
    wavelengths=ls.WavelengthRange(start_nm=400, stop_nm=644, num=81),
)
res = ls.solve(sim)  # exact Mie for a sphere
print(res.q_ext)     # extinction efficiency at each wavelength

Same spec runs with DDA, FDTD, BEM or T-matrix: ls.compare(sim, ["mie", "dda"]).

Materials guide Open a sphere of it in Studio Quick start Ask the community

Lightsmith is open source (MIT): Mie, T-matrix, BEM, DDA, FDTD, RCWA, TMM, mode solvers and inverse design behind one spec, on CPU or GPU. GitHub.

Dispersion formula

Cauchy (formula 5), λ in µm

n = 1.38248838 - 0.00405375 λ^{- 1.0} + 0.00458433 λ^{- 2.0}

Valid from 0.326 to 0.644 µm.

Coefficients as stored

C_i	Value
C1	1.38248838
C2	-0.00405375
C3	-1.0
C4	0.00458433
C5	-2.0

Comments and conditions

n-Heptane; 293 K (20 °C). See the original publication for the expression for n(λ,T).

Conditions

temperature: 293 K

References

K. Kerl and H. Varchmin. Refractive index dispersion (RID) of some liquids in the UV/VIS between 20°C and 60°C. J. Mol. Struct. 349, 257-260 (1995)

doi:10.1016/0022-2860(95)08758-n Refractive index dispersion (RID) of some liquids in the UV/VIS between 20°C and 60°C, Journal of Molecular Structure (1995)

Cite

K. Kerl and H. Varchmin. Refractive index dispersion (RID) of some liquids in the UV/VIS between 20°C and 60°C. Journal of Molecular Structure, 349, 257-260 (1995), doi:10.1016/0022-2860(95)08758-n; Data from the refractiveindex.info database (M. N. Polyanskiy, Sci. Data 11, 94 (2024), doi:10.1038/s41597-023-02898-2)

Data

Computed on 400 wavelengths, the same grid as the API and the library

CSV comma separated TXT tab separated YAML n, k Full database record original YAML All quantities CSV JSON metadata

C7H16 (Heptane), Kerl and Varchmin 1995: n-Heptane; 293 K; n 0.326–0.644 µm: n and k versus wavelength
λ (µm)	n
0.326	1.41319
0.326557	1.413064
0.327114	1.412939
0.327673	1.412814
0.328233	1.412689
0.328793	1.412566
0.329355	1.412442
0.329917	1.412319
0.33048	1.412197
0.331045	1.412074
0.33161	1.411953
0.332176	1.411832
0.332744	1.411711
0.333312	1.411591
0.333881	1.411471
0.334451	1.411351
0.335022	1.411232
0.335595	1.411114
0.336168	1.410996
0.336742	1.410878
0.337317	1.410761
0.337893	1.410644
0.33847	1.410528
0.339048	1.410412
0.339627	1.410296
0.340207	1.410181
0.340788	1.410067
0.34137	1.409953
0.341953	1.409839
0.342537	1.409725
0.343122	1.409613
0.343708	1.4095
0.344295	1.409388
0.344883	1.409276
0.345472	1.409165
0.346062	1.409054
0.346653	1.408944
0.347245	1.408834
0.347838	1.408724
0.348432	1.408615
0.349027	1.408506
0.349623	1.408398
0.35022	1.40829
0.350818	1.408182
0.351417	1.408075
0.352017	1.407968
0.352618	1.407862
0.35322	1.407756
0.353824	1.40765
0.354428	1.407545
0.355033	1.40744
0.355639	1.407336
0.356247	1.407232
0.356855	1.407128
0.357464	1.407025
0.358075	1.406922
0.358686	1.406819
0.359299	1.406717
0.359913	1.406615
0.360527	1.406514
0.361143	1.406413
0.36176	1.406312
0.362377	1.406212
0.362996	1.406112
0.363616	1.406013
0.364237	1.405914
0.364859	1.405815
0.365482	1.405717
0.366106	1.405619
0.366731	1.405521
0.367358	1.405424
0.367985	1.405327
0.368614	1.40523
0.369243	1.405134
0.369874	1.405038
0.370505	1.404943
0.371138	1.404848
0.371772	1.404753
0.372407	1.404658
0.373043	1.404564
0.37368	1.404471
0.374318	1.404377
0.374957	1.404284
0.375597	1.404192
0.376239	1.404099
0.376881	1.404007
0.377525	1.403916
0.37817	1.403824
0.378815	1.403734
0.379462	1.403643
0.38011	1.403553
0.380759	1.403463
0.38141	1.403373
0.382061	1.403284
0.382714	1.403195
0.383367	1.403107
0.384022	1.403018
0.384678	1.40293
0.385334	1.402843
0.385993	1.402756
0.386652	1.402669
0.387312	1.402582
0.387973	1.402496
0.388636	1.40241
0.3893	1.402324
0.389964	1.402239
0.39063	1.402154
0.391298	1.402069
0.391966	1.401985
0.392635	1.401901
0.393306	1.401817
0.393977	1.401734
0.39465	1.401651
0.395324	1.401568
0.395999	1.401486
0.396675	1.401403
0.397353	1.401322
0.398031	1.40124
0.398711	1.401159
0.399392	1.401078
0.400074	1.400997
0.400757	1.400917
0.401442	1.400837
0.402127	1.400757
0.402814	1.400678
0.403502	1.400599
0.404191	1.40052
0.404881	1.400442
0.405573	1.400363
0.406265	1.400285
0.406959	1.400208
0.407654	1.400131
0.40835	1.400054
0.409047	1.399977
0.409746	1.3999
0.410446	1.399824
0.411147	1.399748
0.411849	1.399673
0.412552	1.399597
0.413257	1.399522
0.413962	1.399448
0.414669	1.399373
0.415377	1.399299
0.416087	1.399225
0.416797	1.399152
0.417509	1.399078
0.418222	1.399005
0.418936	1.398932
0.419652	1.39886
0.420368	1.398788
0.421086	1.398716
0.421805	1.398644
0.422526	1.398573
0.423247	1.398502
0.42397	1.398431
0.424694	1.39836
0.425419	1.39829
0.426146	1.39822
0.426874	1.39815
0.427603	1.398081
0.428333	1.398011
0.429064	1.397942
0.429797	1.397874
0.430531	1.397805
0.431266	1.397737
0.432003	1.397669
0.43274	1.397601
0.433479	1.397534
0.43422	1.397467
0.434961	1.3974
0.435704	1.397333
0.436448	1.397267
0.437193	1.397201
0.43794	1.397135
0.438688	1.397069
0.439437	1.397004
0.440187	1.396938
0.440939	1.396874
0.441692	1.396809
0.442446	1.396745
0.443202	1.39668
0.443959	1.396616
0.444717	1.396553
0.445477	1.396489
0.446237	1.396426
0.446999	1.396363
0.447763	1.396301
0.448527	1.396238
0.449293	1.396176
0.450061	1.396114
0.450829	1.396052
0.451599	1.395991
0.45237	1.395929
0.453143	1.395868
0.453917	1.395807
0.454692	1.395747
0.455468	1.395687
0.456246	1.395626
0.457025	1.395567
0.457806	1.395507
0.458588	1.395447
0.459371	1.395388
0.460155	1.395329
0.460941	1.395271
0.461728	1.395212
0.462517	1.395154
0.463306	1.395096
0.464098	1.395038
0.46489	1.39498
0.465684	1.394923
0.466479	1.394866
0.467276	1.394809
0.468074	1.394752
0.468873	1.394695
0.469674	1.394639
0.470476	1.394583
0.47128	1.394527
0.472084	1.394472
0.472891	1.394416
0.473698	1.394361
0.474507	1.394306
0.475317	1.394251
0.476129	1.394197
0.476942	1.394142
0.477757	1.394088
0.478573	1.394034
0.47939	1.39398
0.480209	1.393927
0.481029	1.393873
0.48185	1.39382
0.482673	1.393767
0.483497	1.393715
0.484323	1.393662
0.48515	1.39361
0.485978	1.393558
0.486808	1.393506
0.48764	1.393454
0.488472	1.393403
0.489307	1.393351
0.490142	1.3933
0.490979	1.393249
0.491818	1.393199
0.492658	1.393148
0.493499	1.393098
0.494342	1.393048
0.495186	1.392998
0.496032	1.392948
0.496879	1.392898
0.497727	1.392849
0.498577	1.3928
0.499429	1.392751
0.500281	1.392702
0.501136	1.392654
0.501992	1.392605
0.502849	1.392557
0.503708	1.392509
0.504568	1.392461
0.505429	1.392413
0.506293	1.392366
0.507157	1.392319
0.508023	1.392272
0.508891	1.392225
0.50976	1.392178
0.51063	1.392131
0.511502	1.392085
0.512376	1.392039
0.513251	1.391993
0.514127	1.391947
0.515005	1.391901
0.515885	1.391856
0.516766	1.391811
0.517648	1.391766
0.518532	1.391721
0.519418	1.391676
0.520305	1.391631
0.521193	1.391587
0.522084	1.391543
0.522975	1.391499
0.523868	1.391455
0.524763	1.391411
0.525659	1.391367
0.526557	1.391324
0.527456	1.391281
0.528357	1.391238
0.529259	1.391195
0.530163	1.391152
0.531068	1.39111
0.531975	1.391067
0.532884	1.391025
0.533794	1.390983
0.534705	1.390941
0.535618	1.3909
0.536533	1.390858
0.537449	1.390817
0.538367	1.390775
0.539286	1.390734
0.540207	1.390694
0.54113	1.390653
0.542054	1.390612
0.54298	1.390572
0.543907	1.390532
0.544836	1.390492
0.545766	1.390452
0.546698	1.390412
0.547632	1.390372
0.548567	1.390333
0.549504	1.390293
0.550442	1.390254
0.551382	1.390215
0.552324	1.390176
0.553267	1.390138
0.554212	1.390099
0.555158	1.390061
0.556106	1.390023
0.557056	1.389985
0.558007	1.389947
0.55896	1.389909
0.559915	1.389871
0.560871	1.389834
0.561829	1.389796
0.562788	1.389759
0.563749	1.389722
0.564712	1.389685
0.565676	1.389649
0.566642	1.389612
0.56761	1.389576
0.568579	1.389539
0.56955	1.389503
0.570523	1.389467
0.571497	1.389431
0.572473	1.389396
0.573451	1.38936
0.57443	1.389325
0.575411	1.389289
0.576394	1.389254
0.577378	1.389219
0.578364	1.389184
0.579352	1.389149
0.580341	1.389115
0.581332	1.38908
0.582325	1.389046
0.58332	1.389012
0.584316	1.388978
0.585314	1.388944
0.586313	1.38891
0.587314	1.388876
0.588317	1.388843
0.589322	1.38881
0.590328	1.388776
0.591337	1.388743
0.592346	1.38871
0.593358	1.388677
0.594371	1.388645
0.595386	1.388612
0.596403	1.38858
0.597421	1.388547
0.598442	1.388515
0.599464	1.388483
0.600487	1.388451
0.601513	1.388419
0.60254	1.388388
0.603569	1.388356
0.6046	1.388325
0.605632	1.388293
0.606667	1.388262
0.607703	1.388231
0.60874	1.3882
0.60978	1.38817
0.610821	1.388139
0.611864	1.388108
0.612909	1.388078
0.613956	1.388048
0.615004	1.388017
0.616055	1.387987
0.617107	1.387957
0.618161	1.387928
0.619216	1.387898
0.620274	1.387868
0.621333	1.387839
0.622394	1.38781
0.623457	1.38778
0.624522	1.387751
0.625588	1.387722
0.626656	1.387693
0.627727	1.387665
0.628799	1.387636
0.629872	1.387608
0.630948	1.387579
0.632026	1.387551
0.633105	1.387523
0.634186	1.387495
0.635269	1.387467
0.636354	1.387439
0.637441	1.387411
0.638529	1.387384
0.63962	1.387356
0.640712	1.387329
0.641806	1.387302
0.642902	1.387274
0.644	1.387247

Optical transmission calculator

Free-standing sample in vacuum, normal incidence

Transmittance T: —
Reflectance R: —

Fresnel reflection calculator

R_p: —
R_s: —
R = (R_p+R_s)/2: —
Phase φ_p: —
Phase φ_s: —
Brewster angle θ_B: —
Critical angle θ_C: —

C₇H₁₆ (Heptane): all datasets

About C7H16 (Heptane)

Heptane (C₇H₁₆) is a straight-chain alkane hydrocarbon. It is a clear, colorless liquid that is less dense than water and exhibits a characteristic odor reminiscent of petrol. Being flammable, it is used in many laboratory settings as a non-polar solvent for organic substances. Heptane is also employed as a fuel in various applications and forms a significant component of gasoline. Due to its non-polarity, it is unsuitable for dissolving polar compounds but works effectively with non-polar molecules. In the field of optics, heptane can be used in a variety of experiments and setups that require a liquid medium with specific refractive properties.

More about C7H16 (Heptane) →

Provenance

Version: 1 (snapshot c5c2f18)
Source page: refractiveindex.info
Original file: database/data/organic/C7H16 - heptane/nk/Kerl-293K.yml
ID: ds_4e01682d9aca
API: /v1/datasets/ds_4e01682d9aca

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