I have an equation split into two lines and I'd like to align the terms so that the exponentials and + signs are on top of each other. I have tried as usual with align
and &
, but I cannot get the desired result.
\documentclass{article}
\usepackage{amsmath}
\pagestyle{empty}
\begin{document}
\begin{align*}
\varepsilon(\vec{k})=
\varepsilon_{0} -\alpha - \gamma
&(
%{\phantom{=}}
e^{-i \vec{k} \cdot \vec{\rho}_{1}}
&+ e^{-i \vec{k} \cdot \vec{\rho}_{2}}
&+ e^{-i \vec{k} \cdot \vec{\rho}_{3}}
&+ e^{-i \vec{k} \cdot \vec{\rho}_{4}}
&+ e^{-i \vec{k} \cdot \vec{\rho}_{5}}
&+ e^{-i \vec{k} \cdot \vec{\rho}_{6}}\\
&+ e^{i \vec{k} \cdot \vec{\rho}_{1}}
&+ e^{i \vec{k} \cdot \vec{\rho}_{2}}
&+ e^{i \vec{k} \cdot \vec{\rho}_{3}}
&+ e^{i \vec{k} \cdot \vec{\rho}_{4}}
&+ e^{i \vec{k} \cdot \vec{\rho}_{5}}
&+ e^{i \vec{k} \cdot \vec{\rho}_{6}}
)
\end{align*}
\end{document}
This is what I get. Not all the + signs are aligned in the second line, any clue for a solution?