{"doi":"10.5194/mr-2021-10-cc2","title":"Comment on mr-2021-10: Code availability?","abstract":"<strong class=\"journal-contentHeaderColor\">Abstract.</strong> Double electron–electron resonance (DEER) is a pulse electron paramagnetic resonance (EPR) technique that measures distances between paramagnetic centres. It utilizes a four-pulse sequence based on the refocused Hahn spin echo. The echo decays with increasing pulse sequence length <span class=\"inline-formula\">2(<i>τ</i><sub>1</sub>+<i>τ</i><sub>2</sub>)</span>, where <span class=\"inline-formula\"><i>τ</i><sub>1</sub></span> and <span class=\"inline-formula\"><i>τ</i><sub>2</sub></span> are the two time delays. In DEER, the value of <span class=\"inline-formula\"><i>τ</i><sub>2</sub></span> is determined by the longest inter-spin distance that needs to be resolved, and <span class=\"inline-formula\"><i>τ</i><sub>1</sub></span> is adjusted to maximize the echo amplitude and, thus, sensitivity. We show experimentally that, for typical spin centres (nitroxyl, trityl, and Gd(III)) diluted in frozen protonated solvents, the largest refocused echo amplitude for a given <span class=\"inline-formula\"><i>τ</i><sub>2</sub></span> is obtained neither at very short <span class=\"inline-formula\"><i>τ</i><sub>1</sub></span> (which minimizes the pulse sequence length) nor at <span class=\"inline-formula\"><i>τ</i><sub>1</sub>=<i>τ</i><sub>2</sub></span> (which maximizes dynamic decoupling for a given total sequence length) but rather at <span class=\"inline-formula\"><i>τ</i><sub>1</sub></span> values smaller than <span class=\"inline-formula\"><i>τ</i><sub>2</sub></span>. Large-scale spin dynamics simulations based on the coupled cluster expansion (CCE), including the electron spin and several hundred neighbouring protons, reproduce the experimentally observed behaviour almost quantitatively. They show that electron spin dephasing is driven by solvent protons via the flip-flop coupling among themselves and their hyperfine couplings to the electron spin.","journal":null,"year":2021,"id":229664,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":0,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9521,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2021-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":278274,"name":"Samuel M. Jahn","orcid":"0000-0002-0197-681X","position":1,"is_corresponding":false},{"id":700131,"name":"Akiva Feintuch","orcid":null,"position":2,"is_corresponding":false},{"id":246958,"name":"Stefan Stoll","orcid":"0000-0003-4255-9550","position":3,"is_corresponding":false},{"id":699624,"name":"Daniella Goldfarb","orcid":"0000-0001-5714-7159","position":4,"is_corresponding":false},{"id":700130,"name":"Thorsten Bahrenberg","orcid":null,"position":0,"is_corresponding":true}],"reference_count":32,"raw_metadata":null,"created_at":"2026-07-18T23:55:01.675482Z","pmid":null,"pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}