% !TeX program = pdflatex
% !TeX encoding = utf8
% !TeX spellcheck = ru_Ru
\documentclass[12pt]{article}
%
\usepackage[utf8]{inputenc}
\usepackage[T2A,T1]{fontenc}
\usepackage[ukrainian]{babel}
\usepackage{indentfirst}
\usepackage{misccorr}
\usepackage{cmap}
\usepackage{pgf-spectra}
\begin{document}
\begin{figure}\label{key}
\pgfspectra[axis, begin=780,end=380, width=\textwidth,element=Hg]
\pgfspectra[axis, begin=780,end=380, width=\textwidth,lines={381,480,468,483}]
\end{figure}
\end{document}