Optical constants

Refractive index of C₈H₁₈ (Octane)

Kerl and Varchmin 1995: n-Octane; 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: 1.39885
Extinction coefficient k: 0

Permittivity ε₁: 1.95679
Permittivity ε₂: 0

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

Abbe number V_d: —
Chromatic dispersion dn/dλ: -0.0342745 µm⁻¹

Group index n_g: 1.41899
Group velocity dispersion: 70.8192 fs²/mm

Dispersion parameter D: -386.356 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

# C8H18 (Octane): Kerl and Varchmin 1995: n-Octane; 293 K; n 0.326–0.644 µm
c8h18 = ls.fetch_refractiveindex("organic", "octane", "Kerl-293K", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(c8h18.range_nm)  # (326, 644) nm
eps = c8h18.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_7d4563e2520f/lightsmith"
c8h18 = ls.Tabulated.model_validate(json.load(urllib.request.urlopen(url)))
print(c8h18.source)  # citation and provenance travel with the data

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

# ... load c8h18 as above, then:
sim = ls.Simulation(
    particles=[ls.Particle(shape=ls.Sphere(radius_nm=50), material=c8h18)],
    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 = 1.39260498 - 0.00448963 λ^{- 1.0} + 0.00479591 λ^{- 2.0}

Valid from 0.326 to 0.644 µm.

Coefficients as stored

C_i	Value
C1	1.39260498
C2	-0.00448963
C3	-1.0
C4	0.00479591
C5	-2.0

Comments and conditions

n-Octane; 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

C8H18 (Octane), Kerl and Varchmin 1995: n-Octane; 293 K; n 0.326–0.644 µm: n and k versus wavelength
λ (µm)	n
0.326	1.42396
0.326557	1.42383
0.327114	1.4237
0.327673	1.423571
0.328233	1.423442
0.328793	1.423314
0.329355	1.423186
0.329917	1.423058
0.33048	1.422931
0.331045	1.422805
0.33161	1.422679
0.332176	1.422554
0.332744	1.422429
0.333312	1.422304
0.333881	1.42218
0.334451	1.422056
0.335022	1.421933
0.335595	1.42181
0.336168	1.421688
0.336742	1.421566
0.337317	1.421445
0.337893	1.421324
0.33847	1.421204
0.339048	1.421084
0.339627	1.420964
0.340207	1.420845
0.340788	1.420726
0.34137	1.420608
0.341953	1.42049
0.342537	1.420373
0.343122	1.420256
0.343708	1.420139
0.344295	1.420023
0.344883	1.419908
0.345472	1.419793
0.346062	1.419678
0.346653	1.419564
0.347245	1.41945
0.347838	1.419336
0.348432	1.419223
0.349027	1.419111
0.349623	1.418998
0.35022	1.418887
0.350818	1.418775
0.351417	1.418664
0.352017	1.418554
0.352618	1.418444
0.35322	1.418334
0.353824	1.418225
0.354428	1.418116
0.355033	1.418007
0.355639	1.417899
0.356247	1.417792
0.356855	1.417684
0.357464	1.417578
0.358075	1.417471
0.358686	1.417365
0.359299	1.417259
0.359913	1.417154
0.360527	1.417049
0.361143	1.416945
0.36176	1.416841
0.362377	1.416737
0.362996	1.416634
0.363616	1.416531
0.364237	1.416428
0.364859	1.416326
0.365482	1.416225
0.366106	1.416123
0.366731	1.416022
0.367358	1.415922
0.367985	1.415821
0.368614	1.415721
0.369243	1.415622
0.369874	1.415523
0.370505	1.415424
0.371138	1.415326
0.371772	1.415228
0.372407	1.41513
0.373043	1.415033
0.37368	1.414936
0.374318	1.414839
0.374957	1.414743
0.375597	1.414648
0.376239	1.414552
0.376881	1.414457
0.377525	1.414362
0.37817	1.414268
0.378815	1.414174
0.379462	1.41408
0.38011	1.413987
0.380759	1.413894
0.38141	1.413801
0.382061	1.413709
0.382714	1.413617
0.383367	1.413526
0.384022	1.413435
0.384678	1.413344
0.385334	1.413253
0.385993	1.413163
0.386652	1.413073
0.387312	1.412984
0.387973	1.412895
0.388636	1.412806
0.3893	1.412717
0.389964	1.412629
0.39063	1.412541
0.391298	1.412454
0.391966	1.412367
0.392635	1.41228
0.393306	1.412193
0.393977	1.412107
0.39465	1.412021
0.395324	1.411936
0.395999	1.411851
0.396675	1.411766
0.397353	1.411681
0.398031	1.411597
0.398711	1.411513
0.399392	1.41143
0.400074	1.411346
0.400757	1.411263
0.401442	1.411181
0.402127	1.411098
0.402814	1.411016
0.403502	1.410935
0.404191	1.410853
0.404881	1.410772
0.405573	1.410692
0.406265	1.410611
0.406959	1.410531
0.407654	1.410451
0.40835	1.410372
0.409047	1.410292
0.409746	1.410213
0.410446	1.410135
0.411147	1.410056
0.411849	1.409978
0.412552	1.409901
0.413257	1.409823
0.413962	1.409746
0.414669	1.409669
0.415377	1.409593
0.416087	1.409516
0.416797	1.40944
0.417509	1.409365
0.418222	1.409289
0.418936	1.409214
0.419652	1.409139
0.420368	1.409065
0.421086	1.408991
0.421805	1.408917
0.422526	1.408843
0.423247	1.40877
0.42397	1.408696
0.424694	1.408624
0.425419	1.408551
0.426146	1.408479
0.426874	1.408407
0.427603	1.408335
0.428333	1.408264
0.429064	1.408192
0.429797	1.408121
0.430531	1.408051
0.431266	1.40798
0.432003	1.40791
0.43274	1.40784
0.433479	1.407771
0.43422	1.407702
0.434961	1.407633
0.435704	1.407564
0.436448	1.407495
0.437193	1.407427
0.43794	1.407359
0.438688	1.407291
0.439437	1.407224
0.440187	1.407157
0.440939	1.40709
0.441692	1.407023
0.442446	1.406957
0.443202	1.406891
0.443959	1.406825
0.444717	1.406759
0.445477	1.406694
0.446237	1.406628
0.446999	1.406564
0.447763	1.406499
0.448527	1.406435
0.449293	1.40637
0.450061	1.406306
0.450829	1.406243
0.451599	1.406179
0.45237	1.406116
0.453143	1.406053
0.453917	1.405991
0.454692	1.405928
0.455468	1.405866
0.456246	1.405804
0.457025	1.405742
0.457806	1.405681
0.458588	1.40562
0.459371	1.405559
0.460155	1.405498
0.460941	1.405437
0.461728	1.405377
0.462517	1.405317
0.463306	1.405257
0.464098	1.405198
0.46489	1.405138
0.465684	1.405079
0.466479	1.40502
0.467276	1.404962
0.468074	1.404903
0.468873	1.404845
0.469674	1.404787
0.470476	1.404729
0.47128	1.404672
0.472084	1.404614
0.472891	1.404557
0.473698	1.4045
0.474507	1.404444
0.475317	1.404387
0.476129	1.404331
0.476942	1.404275
0.477757	1.404219
0.478573	1.404164
0.47939	1.404108
0.480209	1.404053
0.481029	1.403998
0.48185	1.403944
0.482673	1.403889
0.483497	1.403835
0.484323	1.403781
0.48515	1.403727
0.485978	1.403673
0.486808	1.40362
0.48764	1.403567
0.488472	1.403514
0.489307	1.403461
0.490142	1.403408
0.490979	1.403356
0.491818	1.403304
0.492658	1.403252
0.493499	1.4032
0.494342	1.403148
0.495186	1.403097
0.496032	1.403046
0.496879	1.402995
0.497727	1.402944
0.498577	1.402893
0.499429	1.402843
0.500281	1.402793
0.501136	1.402743
0.501992	1.402693
0.502849	1.402643
0.503708	1.402594
0.504568	1.402545
0.505429	1.402496
0.506293	1.402447
0.507157	1.402398
0.508023	1.40235
0.508891	1.402302
0.50976	1.402254
0.51063	1.402206
0.511502	1.402158
0.512376	1.402111
0.513251	1.402063
0.514127	1.402016
0.515005	1.401969
0.515885	1.401923
0.516766	1.401876
0.517648	1.40183
0.518532	1.401784
0.519418	1.401738
0.520305	1.401692
0.521193	1.401646
0.522084	1.401601
0.522975	1.401555
0.523868	1.40151
0.524763	1.401465
0.525659	1.401421
0.526557	1.401376
0.527456	1.401332
0.528357	1.401287
0.529259	1.401243
0.530163	1.401199
0.531068	1.401156
0.531975	1.401112
0.532884	1.401069
0.533794	1.401026
0.534705	1.400983
0.535618	1.40094
0.536533	1.400897
0.537449	1.400855
0.538367	1.400812
0.539286	1.40077
0.540207	1.400728
0.54113	1.400686
0.542054	1.400645
0.54298	1.400603
0.543907	1.400562
0.544836	1.400521
0.545766	1.40048
0.546698	1.400439
0.547632	1.400398
0.548567	1.400358
0.549504	1.400318
0.550442	1.400277
0.551382	1.400237
0.552324	1.400197
0.553267	1.400158
0.554212	1.400118
0.555158	1.400079
0.556106	1.40004
0.557056	1.400001
0.558007	1.399962
0.55896	1.399923
0.559915	1.399884
0.560871	1.399846
0.561829	1.399808
0.562788	1.399769
0.563749	1.399731
0.564712	1.399694
0.565676	1.399656
0.566642	1.399618
0.56761	1.399581
0.568579	1.399544
0.56955	1.399507
0.570523	1.39947
0.571497	1.399433
0.572473	1.399396
0.573451	1.39936
0.57443	1.399324
0.575411	1.399287
0.576394	1.399251
0.577378	1.399215
0.578364	1.39918
0.579352	1.399144
0.580341	1.399109
0.581332	1.399073
0.582325	1.399038
0.58332	1.399003
0.584316	1.398968
0.585314	1.398933
0.586313	1.398899
0.587314	1.398864
0.588317	1.39883
0.589322	1.398796
0.590328	1.398762
0.591337	1.398728
0.592346	1.398694
0.593358	1.39866
0.594371	1.398627
0.595386	1.398594
0.596403	1.39856
0.597421	1.398527
0.598442	1.398494
0.599464	1.398461
0.600487	1.398429
0.601513	1.398396
0.60254	1.398364
0.603569	1.398331
0.6046	1.398299
0.605632	1.398267
0.606667	1.398235
0.607703	1.398204
0.60874	1.398172
0.60978	1.39814
0.610821	1.398109
0.611864	1.398078
0.612909	1.398047
0.613956	1.398016
0.615004	1.397985
0.616055	1.397954
0.617107	1.397923
0.618161	1.397893
0.619216	1.397862
0.620274	1.397832
0.621333	1.397802
0.622394	1.397772
0.623457	1.397742
0.624522	1.397712
0.625588	1.397683
0.626656	1.397653
0.627727	1.397624
0.628799	1.397595
0.629872	1.397565
0.630948	1.397536
0.632026	1.397508
0.633105	1.397479
0.634186	1.39745
0.635269	1.397421
0.636354	1.397393
0.637441	1.397365
0.638529	1.397337
0.63962	1.397308
0.640712	1.39728
0.641806	1.397253
0.642902	1.397225
0.644	1.397197

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: —

C₈H₁₈ (Octane): all datasets

About C8H18 (Octane)

Octane (C₈H₁₈) is a straight-chain alkane comprising eight carbon atoms. It is a primary constituent in gasoline and is employed as a reference standard in the octane rating scale, which measures a fuel's ability to resist engine knocking or pinging. As a liquid at room temperature and atmospheric pressure, octane is less dense than water and possesses a characteristic hydrocarbon odor. In the optical domain, octane's properties can be utilized in certain specialized settings. While it's not highly reactive, safety precautions should be followed when handling octane, particularly due to its flammability. Structural formula: CH₃(CH₂)₆CH₃

More about C8H18 (Octane) →

Provenance

Version: 1 (snapshot c5c2f18)
Source page: refractiveindex.info
Original file: database/data/organic/C8H18 - octane/nk/Kerl-293K.yml
ID: ds_7d4563e2520f
API: /v1/datasets/ds_7d4563e2520f

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