Optical constants

Refractive index of C₈H₅KO₄ (Potassium hydrogen phthalate, KHP)

Moutzouris et al. 2011: n(α) 0.450–1.55 µm

Data: formula 4
Range: 0.45–1.551 µm
Temperature: 277.65 K
Optical axis: alpha
Licence: CC0-1.0

Biaxial crystal, axes: alpha

Axis Log x Log y

Click the plot to set the calculator wavelength.

At one wavelength

Refractive index n: 1.66659
Extinction coefficient k: 0

Permittivity ε₁: 2.77751
Permittivity ε₂: 0

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

Abbe number V_d: 24.542
Chromatic dispersion dn/dλ: -0.137735 µm⁻¹

Group index n_g: 1.74752
Group velocity dispersion: 268.957 fs²/mm

Dispersion parameter D: -1467.3 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

# C8H5KO4 (Potassium hydrogen phthalate, KHP): Moutzouris et al. 2011: n(α) 0.450–1.55 µm
c8h5ko4 = ls.fetch_refractiveindex("organic", "potassium_hydrogen_phthalate", "Moutzouris-α", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(c8h5ko4.range_nm)  # (450, 1551) nm
eps = c8h5ko4.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_9f6d869ae329/lightsmith"
c8h5ko4 = ls.Tabulated.model_validate(json.load(urllib.request.urlopen(url)))
print(c8h5ko4.source)  # citation and provenance travel with the data

Any dataset here, as the library's Tabulated material (potassium-hydrogen-phthalate/moutzouris-2011).

# ... load c8h5ko4 as above, then:
sim = ls.Simulation(
    particles=[ls.Particle(shape=ls.Sphere(radius_nm=50), material=c8h5ko4)],
    medium_index=1.0,
    wavelengths=ls.WavelengthRange(start_nm=450, stop_nm=1000, 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

RefractiveIndex.INFO (formula 4), λ in µm

n^{2} = 2.663434655 + \frac{0.037318762 λ^{0.0}}{λ^{2} - {0.175493731}^{2.0}} - 0.013296131 λ^{2.0}

Valid from 0.45 to 1.551 µm.

Coefficients as stored

C_i	Value
C1	2.663434655
C2	0.037318762
C3	0.0
C4	0.175493731
C5	2.0
C6	0.0
C7	0.0
C8	0.0
C9	1.0
C10	-0.013296131
C11	2.0

Comments and conditions

n_α; 24.5 °C (see the original publication for temperature-dependent dispersion formula).

Conditions

temperature: 277.65 K
direction: alpha

References

K. Moutzouris, I. Stavrakas, D. Triantis, M. Enculescub. Temperature-dependent refractive index of potassium acid phthalate (KAP) in the visible and near-infrared. Opt. Mater. 33, 812-816 (2011)

doi:10.1016/j.optmat.2010.12.021 Temperature-dependent refractive index of potassium acid phthalate (KAP) in the visible and near-infrared, Optical Materials (2011)

Cite

K. Moutzouris, I. Stavrakas, D. Triantis and M. Enculescu. Temperature-dependent refractive index of potassium acid phthalate (KAP) in the visible and near-infrared. Optical Materials, 33, 812-816 (2011), doi:10.1016/j.optmat.2010.12.021; 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

C8H5KO4 (Potassium hydrogen phthalate, KHP), Moutzouris et al. 2011: n(α) 0.450–1.55 µm: n and k versus wavelength
λ (µm)	n
0.45	1.696493
0.451398	1.696021
0.4528	1.695553
0.454206	1.695089
0.455617	1.694629
0.457032	1.694172
0.458452	1.693719
0.459876	1.693269
0.461304	1.692823
0.462737	1.69238
0.464174	1.691941
0.465616	1.691505
0.467062	1.691073
0.468513	1.690644
0.469968	1.690218
0.471428	1.689796
0.472892	1.689377
0.474361	1.688961
0.475835	1.688548
0.477313	1.688139
0.478795	1.687732
0.480282	1.687329
0.481774	1.686929
0.483271	1.686532
0.484772	1.686138
0.486277	1.685747
0.487788	1.685359
0.489303	1.684974
0.490823	1.684591
0.492347	1.684212
0.493877	1.683835
0.495411	1.683462
0.496949	1.683091
0.498493	1.682723
0.500041	1.682357
0.501595	1.681995
0.503153	1.681635
0.504715	1.681278
0.506283	1.680923
0.507856	1.680571
0.509433	1.680222
0.511015	1.679875
0.512603	1.679531
0.514195	1.679189
0.515792	1.67885
0.517394	1.678513
0.519001	1.678179
0.520613	1.677847
0.52223	1.677518
0.523852	1.677191
0.52548	1.676866
0.527112	1.676544
0.528749	1.676224
0.530391	1.675906
0.532039	1.675591
0.533691	1.675278
0.535349	1.674967
0.537012	1.674658
0.53868	1.674352
0.540353	1.674048
0.542031	1.673746
0.543715	1.673446
0.545404	1.673148
0.547098	1.672852
0.548797	1.672559
0.550502	1.672267
0.552212	1.671978
0.553927	1.671691
0.555647	1.671405
0.557373	1.671122
0.559105	1.670841
0.560841	1.670561
0.562583	1.670284
0.564331	1.670008
0.566084	1.669735
0.567842	1.669463
0.569606	1.669193
0.571375	1.668925
0.57315	1.668659
0.57493	1.668395
0.576716	1.668132
0.578507	1.667872
0.580304	1.667613
0.582106	1.667356
0.583914	1.6671
0.585728	1.666847
0.587547	1.666595
0.589372	1.666344
0.591203	1.666096
0.593039	1.665849
0.594881	1.665604
0.596729	1.66536
0.598583	1.665119
0.600442	1.664878
0.602307	1.66464
0.604178	1.664403
0.606054	1.664167
0.607937	1.663933
0.609825	1.663701
0.611719	1.66347
0.613619	1.663241
0.615525	1.663013
0.617437	1.662787
0.619355	1.662562
0.621279	1.662339
0.623209	1.662117
0.625144	1.661896
0.627086	1.661677
0.629034	1.66146
0.630988	1.661244
0.632948	1.661029
0.634914	1.660816
0.636886	1.660604
0.638864	1.660393
0.640848	1.660184
0.642839	1.659976
0.644835	1.659769
0.646838	1.659564
0.648847	1.65936
0.650863	1.659157
0.652885	1.658956
0.654912	1.658756
0.656947	1.658557
0.658987	1.658359
0.661034	1.658163
0.663087	1.657968
0.665147	1.657774
0.667213	1.657581
0.669285	1.65739
0.671364	1.6572
0.673449	1.65701
0.675541	1.656822
0.67764	1.656636
0.679744	1.65645
0.681856	1.656265
0.683974	1.656082
0.686098	1.6559
0.688229	1.655719
0.690367	1.655539
0.692511	1.65536
0.694662	1.655182
0.69682	1.655005
0.698984	1.654829
0.701155	1.654654
0.703333	1.654481
0.705518	1.654308
0.707709	1.654137
0.709907	1.653966
0.712112	1.653796
0.714324	1.653628
0.716543	1.65346
0.718769	1.653294
0.721001	1.653128
0.723241	1.652963
0.725487	1.6528
0.727741	1.652637
0.730001	1.652475
0.732269	1.652314
0.734543	1.652154
0.736825	1.651995
0.739113	1.651837
0.741409	1.65168
0.743712	1.651524
0.746022	1.651368
0.748339	1.651214
0.750664	1.65106
0.752995	1.650907
0.755334	1.650755
0.75768	1.650604
0.760034	1.650454
0.762394	1.650304
0.764762	1.650155
0.767138	1.650008
0.769521	1.649861
0.771911	1.649714
0.774308	1.649569
0.776713	1.649424
0.779126	1.64928
0.781546	1.649137
0.783974	1.648995
0.786409	1.648854
0.788851	1.648713
0.791302	1.648573
0.793759	1.648433
0.796225	1.648295
0.798698	1.648157
0.801179	1.64802
0.803667	1.647883
0.806164	1.647748
0.808668	1.647613
0.811179	1.647478
0.813699	1.647345
0.816226	1.647212
0.818762	1.647079
0.821305	1.646948
0.823856	1.646817
0.826415	1.646687
0.828982	1.646557
0.831557	1.646428
0.83414	1.6463
0.83673	1.646172
0.839329	1.646045
0.841936	1.645918
0.844552	1.645792
0.847175	1.645667
0.849806	1.645543
0.852446	1.645419
0.855094	1.645295
0.85775	1.645172
0.860414	1.64505
0.863086	1.644928
0.865767	1.644807
0.868456	1.644686
0.871154	1.644566
0.87386	1.644447
0.876574	1.644328
0.879297	1.644209
0.882028	1.644092
0.884768	1.643974
0.887516	1.643857
0.890272	1.643741
0.893038	1.643625
0.895811	1.64351
0.898594	1.643395
0.901385	1.643281
0.904185	1.643167
0.906993	1.643054
0.909811	1.642941
0.912636	1.642829
0.915471	1.642717
0.918315	1.642605
0.921167	1.642494
0.924028	1.642384
0.926898	1.642274
0.929777	1.642164
0.932665	1.642055
0.935562	1.641947
0.938468	1.641838
0.941383	1.64173
0.944307	1.641623
0.94724	1.641516
0.950183	1.641409
0.953134	1.641303
0.956094	1.641197
0.959064	1.641092
0.962043	1.640987
0.965031	1.640882
0.968029	1.640778
0.971036	1.640674
0.974052	1.640571
0.977077	1.640468
0.980112	1.640365
0.983156	1.640263
0.98621	1.640161
0.989273	1.640059
0.992346	1.639958
0.995428	1.639857
0.99852	1.639756
1.00162	1.639656
1.00473	1.639556
1.00785	1.639456
1.01098	1.639357
1.01412	1.639258
1.01727	1.639159
1.02043	1.639061
1.0236	1.638963
1.02678	1.638865
1.02997	1.638768
1.03317	1.638671
1.03638	1.638574
1.0396	1.638477
1.04283	1.638381
1.04607	1.638285
1.04932	1.638189
1.05258	1.638094
1.05585	1.637998
1.05913	1.637903
1.06242	1.637809
1.06572	1.637714
1.06903	1.63762
1.07235	1.637526
1.07568	1.637432
1.07902	1.637339
1.08237	1.637246
1.08573	1.637152
1.0891	1.63706
1.09249	1.636967
1.09588	1.636875
1.09928	1.636783
1.1027	1.636691
1.10612	1.636599
1.10956	1.636507
1.11301	1.636416
1.11646	1.636325
1.11993	1.636234
1.12341	1.636143
1.1269	1.636052
1.1304	1.635962
1.13391	1.635872
1.13743	1.635782
1.14096	1.635692
1.14451	1.635602
1.14806	1.635512
1.15163	1.635423
1.15521	1.635334
1.15879	1.635245
1.16239	1.635156
1.166	1.635067
1.16963	1.634978
1.17326	1.634889
1.1769	1.634801
1.18056	1.634713
1.18423	1.634624
1.1879	1.634536
1.19159	1.634448
1.1953	1.63436
1.19901	1.634273
1.20273	1.634185
1.20647	1.634097
1.21022	1.63401
1.21397	1.633923
1.21774	1.633835
1.22153	1.633748
1.22532	1.633661
1.22913	1.633574
1.23295	1.633487
1.23677	1.6334
1.24062	1.633313
1.24447	1.633226
1.24834	1.63314
1.25221	1.633053
1.2561	1.632966
1.26	1.63288
1.26392	1.632793
1.26784	1.632707
1.27178	1.632621
1.27573	1.632534
1.27969	1.632448
1.28367	1.632362
1.28766	1.632275
1.29166	1.632189
1.29567	1.632103
1.29969	1.632016
1.30373	1.63193
1.30778	1.631844
1.31184	1.631758
1.31592	1.631672
1.32	1.631585
1.3241	1.631499
1.32822	1.631413
1.33234	1.631327
1.33648	1.63124
1.34063	1.631154
1.34479	1.631068
1.34897	1.630981
1.35316	1.630895
1.35736	1.630809
1.36158	1.630722
1.36581	1.630636
1.37005	1.630549
1.37431	1.630463
1.37858	1.630376
1.38286	1.630289
1.38715	1.630203
1.39146	1.630116
1.39578	1.630029
1.40012	1.629942
1.40447	1.629855
1.40883	1.629768
1.41321	1.629681
1.4176	1.629593
1.422	1.629506
1.42642	1.629419
1.43085	1.629331
1.43529	1.629243
1.43975	1.629156
1.44422	1.629068
1.44871	1.62898
1.45321	1.628892
1.45772	1.628804
1.46225	1.628715
1.46679	1.628627
1.47135	1.628538
1.47592	1.62845
1.4805	1.628361
1.4851	1.628272
1.48971	1.628183
1.49434	1.628094
1.49898	1.628004
1.50364	1.627915
1.50831	1.627825
1.51299	1.627735
1.51769	1.627645
1.52241	1.627555
1.52714	1.627465
1.53188	1.627374
1.53664	1.627284
1.54141	1.627193
1.5462	1.627102
1.551	1.627011

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: —

C₈H₅KO₄ (Potassium hydrogen phthalate, KHP): all datasets

About C8H5KO4 (Potassium hydrogen phthalate, KHP)

Potassium hydrogen phthalate (C₈H₅KO₄) is a white crystalline salt commonly referred to as KHP. Due to its high purity and stability, KHP is frequently utilized as a primary standard for acid-base titrations. This means it has a well-known and stable stoichiometry, which is essential for accurate volumetric analyses. Another key characteristic of KHP is its low hygroscopicity, allowing it to be easily weighed accurately without the worry of moisture absorption skewing the results. In the optics domain, as with many salts, KHP can be utilized to produce specific refractive properties when dissolved in a solvent or integrated within composite materials. Besides its laboratory applications, potassium hydrogen phthalate serves as a buffer solution and can be used in the preparation of certain pharmaceuticals.

Potassium hydrogen phthalate - Wikipedia

More about C8H5KO4 (Potassium hydrogen phthalate, KHP) →

Provenance

Version: 1 (snapshot c5c2f18)
Source page: refractiveindex.info
Original file: database/data/organic/C8H5KO4 - potassium hydrogen phthalate/nk/Moutzouris-alpha.yml
ID: ds_9f6d869ae329
API: /v1/datasets/ds_9f6d869ae329

Plot