Optical constants

Refractive index of CsCl (Cesium chloride)

Li 1976: n 0.18–40 µm

Data: formula 1
Range: 0.18–40 µm
Licence: CC0-1.0

Axis Log x Log y

Click the plot to set the calculator wavelength.

At one wavelength

Refractive index n: 1.6403
Extinction coefficient k: 0

Permittivity ε₁: 2.6906
Permittivity ε₂: 0

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

Abbe number V_d: 43.922
Chromatic dispersion dn/dλ: -0.074242 µm⁻¹

Group index n_g: 1.68393
Group velocity dispersion: 145.106 fs²/mm

Dispersion parameter D: -791.632 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

# CsCl (Cesium chloride): Li 1976: n 0.18–40 µm
cscl = ls.fetch_refractiveindex("main", "CsCl", "Li", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(cscl.range_nm)  # (180, 40000) nm
eps = cscl.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_01938a699a19/lightsmith"
cscl = ls.Tabulated.model_validate(json.load(urllib.request.urlopen(url)))
print(cscl.source)  # citation and provenance travel with the data

Any dataset here, as the library's Tabulated material (cscl/li-1976).

# ... load cscl as above, then:
sim = ls.Simulation(
    particles=[ls.Particle(shape=ls.Sphere(radius_nm=50), material=cscl)],
    medium_index=1.0,
    wavelengths=ls.WavelengthRange(start_nm=400, 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"]).

import json, urllib.request
import lightsmith as ls

url = "https://materials.lightsmith.dev/v1/datasets/ds_01938a699a19/lightsmith?model=drude_lorentz"
cscl_dl = ls.DrudeLorentz.model_validate(json.load(urllib.request.urlopen(url)))

A dispersive Drude–Lorentz model for time-domain solvers.

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

Sellmeier (formula 1), λ in µm

n^{2} - 1 = 0.33013 + \frac{0.98369 λ^{2}}{λ^{2} - {0.119}^{2}} + \frac{9 \times 10^{-5} λ^{2}}{λ^{2} - {0.137}^{2}} + \frac{0.00018 λ^{2}}{λ^{2} - {0.145}^{2}} + \frac{0.30914 λ^{2}}{λ^{2} - {0.162}^{2}} + \frac{4.32 λ^{2}}{λ^{2} - {100.5}^{2}}

Valid from 0.18 to 40.0 µm.

Coefficients as stored

C_i	Value
C1	0.33013
C2	0.98369
C3	0.119
C4	9e-05
C5	0.137
C6	0.00018
C7	0.145
C8	0.30914
C9	0.162
C10	4.32
C11	100.5

Comments and conditions

297 K (24 °C).

References

H. H. Li. Refractive index of alkali halides and its wavelength and temperature derivatives. J. Phys. Chem. Ref. Data 5, 329-528 (1976) and references therein.
* Sellmeier formula is derived by critical analysis of experimental data from several sources.

doi:10.1063/1.555536 Refractive index of alkali halides and its wavelength and temperature derivatives, Journal of Physical and Chemical Reference Data (1976)

Cite

H. H. Li. Refractive index of alkali halides and its wavelength and temperature derivatives. Journal of Physical and Chemical Reference Data, 5, 329-528 (1976), doi:10.1063/1.555536; 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

CsCl (Cesium chloride), Li 1976: n 0.18–40 µm: n and k versus wavelength
λ (µm)	n
0.18	2.169178
0.182454	2.122118
0.184942	2.082766
0.187464	2.049199
0.19002	2.020103
0.192611	1.994553
0.195237	1.971873
0.197899	1.951558
0.200598	1.933221
0.203333	1.91656
0.206105	1.901337
0.208916	1.887357
0.211764	1.874464
0.214652	1.862528
0.217578	1.851438
0.220545	1.841105
0.223552	1.83145
0.226601	1.822405
0.22969	1.813915
0.232822	1.805927
0.235997	1.798398
0.239215	1.79129
0.242476	1.784569
0.245783	1.778204
0.249134	1.772169
0.252531	1.766438
0.255974	1.760991
0.259464	1.755807
0.263002	1.75087
0.266588	1.746162
0.270223	1.741669
0.273908	1.737378
0.277643	1.733276
0.281428	1.729353
0.285266	1.725597
0.289155	1.722
0.293098	1.718551
0.297094	1.715245
0.301145	1.712071
0.305251	1.709025
0.309414	1.706098
0.313633	1.703285
0.317909	1.700581
0.322244	1.69798
0.326638	1.695477
0.331091	1.693067
0.335606	1.690746
0.340182	1.688509
0.34482	1.686354
0.349522	1.684277
0.354288	1.682273
0.359119	1.68034
0.364015	1.678475
0.368979	1.676674
0.37401	1.674936
0.379109	1.673257
0.384279	1.671635
0.389518	1.670067
0.394829	1.668553
0.400213	1.667089
0.40567	1.665673
0.411201	1.664303
0.416808	1.662979
0.422491	1.661698
0.428252	1.660458
0.434091	1.659257
0.44001	1.658096
0.44601	1.656971
0.452091	1.655882
0.458256	1.654827
0.464504	1.653805
0.470838	1.652815
0.477258	1.651856
0.483765	1.650926
0.490361	1.650025
0.497048	1.649152
0.503825	1.648306
0.510695	1.647485
0.517658	1.646689
0.524716	1.645917
0.531871	1.645169
0.539123	1.644442
0.546474	1.643738
0.553925	1.643055
0.561478	1.642391
0.569134	1.641748
0.576894	1.641123
0.584761	1.640517
0.592734	1.639929
0.600816	1.639358
0.609008	1.638803
0.617312	1.638265
0.625729	1.637742
0.634261	1.637235
0.642909	1.636742
0.651676	1.636263
0.660561	1.635798
0.669568	1.635346
0.678698	1.634908
0.687952	1.634481
0.697332	1.634067
0.706841	1.633665
0.716478	1.633274
0.726248	1.632894
0.73615	1.632525
0.746188	1.632166
0.756362	1.631817
0.766675	1.631478
0.777129	1.631148
0.787725	1.630828
0.798466	1.630516
0.809353	1.630214
0.820389	1.629919
0.831575	1.629633
0.842914	1.629354
0.854407	1.629083
0.866057	1.62882
0.877866	1.628564
0.889836	1.628315
0.901969	1.628072
0.914267	1.627837
0.926734	1.627607
0.93937	1.627384
0.952178	1.627167
0.965161	1.626955
0.978322	1.62675
0.991661	1.62655
1.00518	1.626355
1.01889	1.626165
1.03278	1.62598
1.04686	1.625801
1.06114	1.625626
1.07561	1.625455
1.09027	1.625289
1.10514	1.625128
1.12021	1.62497
1.13548	1.624817
1.15096	1.624668
1.16666	1.624522
1.18257	1.62438
1.19869	1.624242
1.21503	1.624107
1.2316	1.623976
1.24839	1.623848
1.26542	1.623723
1.28267	1.623601
1.30016	1.623483
1.31789	1.623367
1.33586	1.623254
1.35407	1.623143
1.37254	1.623036
1.39125	1.622931
1.41022	1.622828
1.42945	1.622728
1.44894	1.62263
1.4687	1.622534
1.48872	1.622441
1.50902	1.62235
1.5296	1.62226
1.55045	1.622173
1.57159	1.622088
1.59302	1.622004
1.61474	1.621922
1.63676	1.621842
1.65908	1.621764
1.6817	1.621687
1.70463	1.621611
1.72787	1.621538
1.75143	1.621465
1.77531	1.621394
1.79952	1.621324
1.82406	1.621256
1.84893	1.621189
1.87414	1.621122
1.89969	1.621057
1.9256	1.620993
1.95185	1.620931
1.97847	1.620869
2.00544	1.620807
2.03279	1.620747
2.0605	1.620688
2.0886	1.620629
2.11708	1.620572
2.14595	1.620514
2.17521	1.620458
2.20486	1.620402
2.23493	1.620347
2.2654	1.620292
2.29629	1.620238
2.3276	1.620184
2.35934	1.62013
2.39151	1.620077
2.42412	1.620024
2.45717	1.619972
2.49067	1.61992
2.52464	1.619868
2.55906	1.619816
2.59395	1.619764
2.62932	1.619713
2.66517	1.619661
2.70151	1.61961
2.73835	1.619558
2.77569	1.619506
2.81353	1.619455
2.8519	1.619403
2.89078	1.619351
2.9302	1.619299
2.97015	1.619246
3.01065	1.619193
3.0517	1.61914
3.09331	1.619087
3.13549	1.619033
3.17824	1.618979
3.22158	1.618924
3.26551	1.618869
3.31003	1.618813
3.35516	1.618756
3.40091	1.618699
3.44729	1.618641
3.49429	1.618583
3.54193	1.618523
3.59023	1.618463
3.63918	1.618402
3.6888	1.61834
3.7391	1.618277
3.79008	1.618213
3.84176	1.618148
3.89415	1.618082
3.94724	1.618015
4.00106	1.617947
4.05562	1.617877
4.11092	1.617806
4.16697	1.617734
4.22379	1.61766
4.28138	1.617585
4.33976	1.617508
4.39893	1.617429
4.45891	1.61735
4.51971	1.617268
4.58134	1.617184
4.64381	1.617099
4.70712	1.617012
4.77131	1.616923
4.83636	1.616832
4.90231	1.616739
4.96915	1.616644
5.03691	1.616546
5.10559	1.616446
5.1752	1.616344
5.24577	1.616239
5.31729	1.616132
5.3898	1.616022
5.46329	1.61591
5.53778	1.615795
5.61329	1.615677
5.68983	1.615556
5.76741	1.615432
5.84605	1.615304
5.92576	1.615174
6.00656	1.61504
6.08846	1.614903
6.17148	1.614762
6.25563	1.614618
6.34092	1.61447
6.42738	1.614318
6.51502	1.614162
6.60385	1.614002
6.6939	1.613838
6.78517	1.613669
6.87769	1.613496
6.97147	1.613318
7.06652	1.613136
7.16288	1.612949
7.26054	1.612756
7.35954	1.612559
7.45989	1.612356
7.56161	1.612148
7.66471	1.611934
7.76922	1.611714
7.87516	1.611489
7.98254	1.611257
8.09138	1.611019
8.20171	1.610774
8.31354	1.610523
8.4269	1.610265
8.5418	1.609999
8.65827	1.609727
8.77632	1.609447
8.89599	1.609159
9.01729	1.608863
9.14024	1.608559
9.26487	1.608247
9.3912	1.607926
9.51925	1.607596
9.64905	1.607257
9.78061	1.606908
9.91397	1.60655
10.0492	1.606182
10.1862	1.605803
10.3251	1.605414
10.4658	1.605014
10.6086	1.604602
10.7532	1.604179
10.8998	1.603744
11.0484	1.603297
11.1991	1.602837
11.3518	1.602365
11.5066	1.601878
11.6635	1.601379
11.8225	1.600864
11.9837	1.600336
12.1471	1.599792
12.3127	1.599233
12.4806	1.598657
12.6508	1.598066
12.8233	1.597457
12.9981	1.596831
13.1754	1.596187
13.355	1.595524
13.5371	1.594842
13.7217	1.594141
13.9088	1.593419
14.0984	1.592677
14.2907	1.591913
14.4855	1.591127
14.683	1.590318
14.8833	1.589485
15.0862	1.588628
15.2919	1.587746
15.5004	1.586838
15.7118	1.585903
15.926	1.584941
16.1431	1.583951
16.3633	1.582931
16.5864	1.581881
16.8125	1.5808
17.0418	1.579687
17.2741	1.578541
17.5097	1.57736
17.7484	1.576144
17.9904	1.574892
18.2357	1.573602
18.4844	1.572272
18.7364	1.570903
18.9919	1.569492
19.2508	1.568038
19.5133	1.56654
19.7794	1.564996
20.0491	1.563404
20.3225	1.561764
20.5996	1.560072
20.8804	1.558329
21.1652	1.556531
21.4537	1.554676
21.7463	1.552764
22.0428	1.550791
22.3433	1.548757
22.648	1.546657
22.9568	1.544491
23.2698	1.542255
23.5871	1.539948
23.9087	1.537566
24.2347	1.535107
24.5652	1.532568
24.9001	1.529946
25.2396	1.527237
25.5838	1.524439
25.9326	1.521548
26.2862	1.51856
26.6446	1.515472
27.0079	1.51228
27.3762	1.508978
27.7495	1.505564
28.1278	1.502033
28.5114	1.498379
28.9001	1.494597
29.2942	1.490682
29.6936	1.486629
30.0985	1.482432
30.5089	1.478083
30.9249	1.473577
31.3466	1.468907
31.774	1.464064
32.2072	1.459042
32.6464	1.453831
33.0915	1.448424
33.5427	1.442809
34.0001	1.436979
34.4637	1.430921
34.9336	1.424624
35.4099	1.418077
35.8927	1.411266
36.3821	1.404178
36.8782	1.396798
37.3811	1.389109
37.8908	1.381095
38.4074	1.372737
38.9311	1.364016
39.4619	1.35491
40	1.345396

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: —

CsCl (Cesium chloride): all datasets

Li 1976: n 0.18–40 µm n 0.18–40 µm default

About CsCl (Cesium chloride)

Caesium chloride (CsCl) is an inorganic compound that forms colorless, water-soluble crystals with a simple cubic structure. It is widely used in various applications, including as an electrolyte in electrochemical studies and as a source of caesium ions in chemical processes. One of its most notable uses is in molecular biology for density gradient ultracentrifugation, where it effectively separates various types of DNA. Specifically, CsCl gradients are highly effective for isolating plasmid DNA from other cellular components. Although it has considerable utility in laboratory settings, caesium chloride must be handled with care. It can be corrosive, and excessive exposure can pose health risks, such as disruptions in cellular potassium ion channels that could lead to arrhythmias. Therefore, strict safety protocols are required for its handling and storage. Overall, CsCl is a compound of significant importance in both scientific research and industrial applications.

Caesium chloride - Wikipedia

More about CsCl (Cesium chloride) →

Provenance

Version: 1 (snapshot c5c2f18)
Source page: refractiveindex.info
Original file: database/data/main/CsCl/nk/Li.yml
ID: ds_01938a699a19
API: /v1/datasets/ds_01938a699a19

Plot