The same plot in 14 other libraries — Python: Altair, Bokeh, Matplotlib, Plotly, plotnine, Pygal, Seaborn; R: ggplot2; Julia: Makie.jl; JavaScript: Chart.js, D3.js, Apache ECharts, Highcharts, MUI X Charts. Compare all 15 side by side: NMR Spectrum (Nuclear Magnetic Resonance) in Python, R, Julia and JavaScript.
An NMR spectrum plots signal intensity versus chemical shift (in ppm) to reveal the electronic environment of atomic nuclei in a molecule. It is the primary analytical tool in organic chemistry for determining molecular structure, with peak positions indicating functional groups and splitting patterns (multiplets) revealing connectivity between neighboring atoms. The x-axis is conventionally reversed (high ppm on the left) and peaks appear as sharp signals rising from a baseline.
""" anyplot.ai
spectrum-nmr: NMR Spectrum (Nuclear Magnetic Resonance)
Library: letsplot 4.10.1 | Python 3.13.13
Quality: 91/100 | Updated: 2026-06-03
"""
import os
import numpy as np
import pandas as pd
from lets_plot import (
LetsPlot,
aes,
element_blank,
element_line,
element_rect,
element_text,
geom_area,
geom_hline,
geom_line,
geom_text,
ggplot,
ggsize,
labs,
layer_tooltips,
scale_x_reverse,
scale_y_continuous,
theme,
theme_minimal,
)
from lets_plot.export import ggsave
LetsPlot.setup_html()
# Theme tokens (Imprint palette — see prompts/default-style-guide.md)
THEME = os.getenv("ANYPLOT_THEME", "light")
PAGE_BG = "#FAF8F1" if THEME == "light" else "#1A1A17"
INK = "#1A1A17" if THEME == "light" else "#F0EFE8"
INK_SOFT = "#4A4A44" if THEME == "light" else "#B8B7B0"
BRAND = "#009E73" # Imprint palette position 1 — ALWAYS first series
# Data - Synthetic 1H NMR spectrum of ethanol (CH3CH2OH)
np.random.seed(42)
chemical_shift = np.linspace(5.0, -0.5, 5000)
w = 0.008 # Lorentzian half-width for sharp peaks
# Build spectrum by summing Lorentzian peaks: A * w^2 / ((x - c)^2 + w^2)
intensity = np.zeros_like(chemical_shift)
# TMS reference peak at 0 ppm
intensity += 1.0 * w**2 / ((chemical_shift - 0.0) ** 2 + w**2)
# CH3 triplet near 1.18 ppm (J-coupling = 0.06 ppm, intensity ratio 1:2:1)
j = 0.06
for center, amp in [(1.18 - j, 0.75), (1.18, 1.5), (1.18 + j, 0.75)]:
intensity += amp * w**2 / ((chemical_shift - center) ** 2 + w**2)
# CH2 quartet near 3.69 ppm (J-coupling = 0.06 ppm, intensity ratio 1:3:3:1)
for center, amp in [(3.69 - 1.5 * j, 0.4), (3.69 - 0.5 * j, 1.2), (3.69 + 0.5 * j, 1.2), (3.69 + 1.5 * j, 0.4)]:
intensity += amp * w**2 / ((chemical_shift - center) ** 2 + w**2)
# OH singlet near 2.61 ppm (broader due to exchange)
w_oh = 0.012
intensity += 0.6 * w_oh**2 / ((chemical_shift - 2.61) ** 2 + w_oh**2)
# Add subtle baseline noise
intensity += np.random.normal(0, 0.003, len(chemical_shift))
intensity = np.clip(intensity, 0, None)
df = pd.DataFrame({"chemical_shift": chemical_shift, "intensity": intensity})
# Peak labels positioned above each peak group
peak_labels = pd.DataFrame(
{
"x": [0.0, 1.18, 2.61, 3.69],
"y": [1.15, 1.58, 0.78, 1.42],
"label": ["TMS\n0.00 ppm", "CH₃ (triplet)\n1.18 ppm", "OH (singlet)\n2.61 ppm", "CH₂ (quartet)\n3.69 ppm"],
}
)
# Interactive tooltips — distinctly lets-plot (not available in plotnine)
spectrum_tooltips = (
layer_tooltips()
.format("@{chemical_shift}", ".3f")
.line("δ: @{chemical_shift} ppm")
.format("@{intensity}", ".4f")
.line("Intensity: @{intensity} a.u.")
)
# Plot — geom_area fill gives distinctive spectrum appearance; tooltips add interactive HTML layer
plot = (
ggplot(df, aes(x="chemical_shift", y="intensity"))
+ geom_hline(yintercept=0, color=INK_SOFT, size=0.5)
+ geom_area(fill=BRAND, alpha=0.15)
+ geom_line(color=BRAND, size=1.2, tooltips=spectrum_tooltips)
+ geom_text(data=peak_labels, mapping=aes(x="x", y="y", label="label"), size=5.5, color=INK, fontface="bold")
+ labs(
x="δ Chemical Shift (ppm)",
y="Intensity (a.u.)",
title="Ethanol ¹H NMR · spectrum-nmr · python · letsplot · anyplot.ai",
)
+ scale_x_reverse(limits=[-0.5, 5.0])
+ scale_y_continuous(expand=[0.02, 0, 0.20, 0])
+ theme_minimal()
+ theme(
plot_background=element_rect(fill=PAGE_BG, color=PAGE_BG),
panel_background=element_rect(fill=PAGE_BG),
panel_grid_major_x=element_blank(),
panel_grid_major_y=element_line(color=INK_SOFT, size=0.2),
panel_grid_minor=element_blank(),
axis_title=element_text(size=12, color=INK),
axis_text=element_text(size=10, color=INK_SOFT),
plot_title=element_text(size=16, color=INK),
axis_line=element_line(color=INK_SOFT),
axis_ticks=element_blank(),
plot_margin=[30, 40, 20, 20],
)
+ ggsize(800, 450)
)
# Save
ggsave(plot, f"plot-{THEME}.png", path=".", scale=4)
ggsave(plot, f"plot-{THEME}.html", path=".")
Runnable source as JSON, for any HTTP client: https://api.anyplot.ai/specs/spectrum-nmr/letsplot/code. Any spec id and library id listed in llms-full.txt fit the same URL shape; every URL below is complete and callable.
{
"spec_id": "spectrum-nmr",
"language": "python",
"library": "letsplot",
"page": "https://anyplot.ai/spectrum-nmr/python/letsplot",
"hub": "https://anyplot.ai/spectrum-nmr",
"code_json": "https://api.anyplot.ai/specs/spectrum-nmr/letsplot/code",
"spec_json": "https://api.anyplot.ai/specs/spectrum-nmr",
"render_light_png": "https://storage.googleapis.com/anyplot-images/plots/spectrum-nmr/python/letsplot/plot-light.png",
"render_dark_png": "https://storage.googleapis.com/anyplot-images/plots/spectrum-nmr/python/letsplot/plot-dark.png",
"interactive_light_html": "https://storage.googleapis.com/anyplot-images/plots/spectrum-nmr/python/letsplot/plot-light.html",
"interactive_dark_html": "https://storage.googleapis.com/anyplot-images/plots/spectrum-nmr/python/letsplot/plot-dark.html",
"quality_score": 91.0,
"license": "MIT",
"guide": "https://anyplot.ai/llms.txt"
}Part of NMR Spectrum (Nuclear Magnetic Resonance) on anyplot.ai.