@article {44617,
	title = {Lower scaling approximation to EOM-CCSD: a critical assessment of the ionization problem},
	journal = {International Journal of Quantum Chemistry},
	volume = {118},
	year = {2018},
	month = {JUL},
	pages = {e25594},
	abstract = {<p>In this article, we investigate the performance of different approximate variants of the EOM-CCSD method for calculation of ionization potential (IP), as compared to EOM-CCSDT reference values. None of the lower scaling approximations to the EOM-CCSD method give a consistent performance for valence, inner valence, and core ionization, favoring one, or the other depending on the nature of the approximation used. The parent EOMIP-CCSD method gives superior performance for valence IP but can show large errors for inner valence and core ionization. The problem is particularly severe for core-ionization, where even the EOMIP-CCSDT method cannot provide quantitative accuracy.</p>},
	keywords = {EOM-CCSD, Ionization potential, lower scaling},
	issn = {0020-7608},
	doi = {10.1002/qua.25594},
	author = {Dutta, Achintya Kumar and Vaval, Nayana and Pal, Sourav}
}
